Rename ERC interfaces to I prefix

contracts/crowdsale/Crowdsale.sol

@@ -19,10 +19,10 @@ import "../token/ERC20/SafeERC20.sol";
  */
 contract Crowdsale {
   using SafeMath for uint256;
-  using SafeERC20 for ERC20;
+  using SafeERC20 for IERC20;
 
   // The token being sold
-  ERC20 public token;
+  IERC20 public token;
 
   // Address where funds are collected
   address public wallet;
@@ -55,7 +55,7 @@ contract Crowdsale {
    * @param _wallet Address where collected funds will be forwarded to
    * @param _token Address of the token being sold
    */
-  constructor(uint256 _rate, address _wallet, ERC20 _token) public {
+  constructor(uint256 _rate, address _wallet, IERC20 _token) public {
     require(_rate > 0);
     require(_wallet != address(0));
     require(_token != address(0));

contracts/crowdsale/emission/AllowanceCrowdsale.sol

@@ -12,7 +12,7 @@ import "../../math/SafeMath.sol";
  */
 contract AllowanceCrowdsale is Crowdsale {
   using SafeMath for uint256;
-  using SafeERC20 for ERC20;
+  using SafeERC20 for IERC20;
 
   address public tokenWallet;
 

contracts/lifecycle/TokenDestructible.sol

@@ -25,7 +25,7 @@ contract TokenDestructible is Ownable {
 
     // Transfer tokens to owner
     for (uint256 i = 0; i < _tokens.length; i++) {
-      ERC20 token = ERC20(_tokens[i]);
+      IERC20 token = IERC20(_tokens[i]);
       uint256 balance = token.balanceOf(this);
       token.transfer(owner, balance);
     }

contracts/mocks/AllowanceCrowdsaleImpl.sol

@@ -9,7 +9,7 @@ contract AllowanceCrowdsaleImpl is AllowanceCrowdsale {
   constructor (
     uint256 _rate,
     address _wallet,
-    ERC20 _token,
+    IERC20 _token,
     address _tokenWallet
   )
     public

contracts/mocks/CappedCrowdsaleImpl.sol

@@ -9,7 +9,7 @@ contract CappedCrowdsaleImpl is CappedCrowdsale {
   constructor (
     uint256 _rate,
     address _wallet,
-    ERC20 _token,
+    IERC20 _token,
     uint256 _cap
   )
     public

contracts/mocks/IncreasingPriceCrowdsaleImpl.sol

@@ -10,7 +10,7 @@ contract IncreasingPriceCrowdsaleImpl is IncreasingPriceCrowdsale {
     uint256 _openingTime,
     uint256 _closingTime,
     address _wallet,
-    ERC20 _token,
+    IERC20 _token,
     uint256 _initialRate,
     uint256 _finalRate
   )

contracts/mocks/IndividuallyCappedCrowdsaleImpl.sol

@@ -9,7 +9,7 @@ contract IndividuallyCappedCrowdsaleImpl is IndividuallyCappedCrowdsale {
   constructor (
     uint256 _rate,
     address _wallet,
-    ERC20 _token
+    IERC20 _token
   )
     public
     Crowdsale(_rate, _wallet, _token)

contracts/mocks/PostDeliveryCrowdsaleImpl.sol

@@ -11,7 +11,7 @@ contract PostDeliveryCrowdsaleImpl is PostDeliveryCrowdsale {
     uint256 _closingTime,
     uint256 _rate,
     address _wallet,
-    ERC20 _token
+    IERC20 _token
   )
     public
     TimedCrowdsale(_openingTime, _closingTime)

contracts/mocks/SafeERC20Helper.sol

@@ -4,7 +4,7 @@ import "../token/ERC20/ERC20.sol";
 import "../token/ERC20/SafeERC20.sol";
 
 
-contract ERC20FailingMock is ERC20 {
+contract ERC20FailingMock is IERC20 {
   function totalSupply() public view returns (uint256) {
     return 0;
   }
@@ -31,7 +31,7 @@ contract ERC20FailingMock is ERC20 {
 }
 
 
-contract ERC20SucceedingMock is ERC20 {
+contract ERC20SucceedingMock is IERC20 {
   function totalSupply() public view returns (uint256) {
     return 0;
   }
@@ -59,10 +59,10 @@ contract ERC20SucceedingMock is ERC20 {
 
 
 contract SafeERC20Helper {
-  using SafeERC20 for ERC20;
+  using SafeERC20 for IERC20;
 
-  ERC20 failing;
-  ERC20 succeeding;
+  IERC20 failing;
+  IERC20 succeeding;
 
   constructor() public {
     failing = new ERC20FailingMock();

contracts/mocks/TimedCrowdsaleImpl.sol

@@ -11,7 +11,7 @@ contract TimedCrowdsaleImpl is TimedCrowdsale {
     uint256 _closingTime,
     uint256 _rate,
     address _wallet,
-    ERC20 _token
+    IERC20 _token
   )
     public
     Crowdsale(_rate, _wallet, _token)

contracts/mocks/WhitelistedCrowdsaleImpl.sol

@@ -10,7 +10,7 @@ contract WhitelistedCrowdsaleImpl is Crowdsale, WhitelistedCrowdsale {
   constructor (
     uint256 _rate,
     address _wallet,
-    ERC20 _token
+    IERC20 _token
   )
     Crowdsale(_rate, _wallet, _token)
     public

contracts/ownership/CanReclaimToken.sol

@@ -12,13 +12,13 @@ import "../token/ERC20/SafeERC20.sol";
  * This will prevent any accidental loss of tokens.
  */
 contract CanReclaimToken is Ownable {
-  using SafeERC20 for ERC20;
+  using SafeERC20 for IERC20;
 
   /**
    * @dev Reclaim all ERC20 compatible tokens
    * @param _token ERC20 The address of the token contract
    */
-  function reclaimToken(ERC20 _token) external onlyOwner {
+  function reclaimToken(IERC20 _token) external onlyOwner {
     uint256 balance = _token.balanceOf(this);
     _token.safeTransfer(owner, balance);
   }

contracts/proposals/ERC1046/TokenMetadata.sol

@@ -9,7 +9,7 @@ import "../../token/ERC20/ERC20.sol";
  * @dev tokenURI must respond with a URI that implements https://eips.ethereum.org/EIPS/eip-1047
  * @dev TODO - update https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC721/ERC721.sol#L17 when 1046 is finalized
  */
-contract ERC20TokenMetadata is ERC20 {
+contract ERC20TokenMetadata is IERC20 {
   function tokenURI() external view returns (string);
 }
 

contracts/token/ERC20/DetailedERC20.sol

@@ -9,7 +9,7 @@ import "./ERC20.sol";
  * All the operations are done using the smallest and indivisible token unit,
  * just as on Ethereum all the operations are done in wei.
  */
-contract DetailedERC20 is ERC20 {
+contract DetailedERC20 is IERC20 {
   string public name;
   string public symbol;
   uint8 public decimals;

contracts/token/ERC20/ERC20.sol

@@ -5,7 +5,7 @@ pragma solidity ^0.4.24;
  * @title ERC20 interface
  * @dev see https://github.com/ethereum/EIPs/issues/20
  */
-contract ERC20 {
+interface IERC20 {
   function totalSupply() public view returns (uint256);
 
   function balanceOf(address _who) public view returns (uint256);

contracts/token/ERC20/SafeERC20.sol

@@ -12,7 +12,7 @@ import "./ERC20.sol";
  */
 library SafeERC20 {
   function safeTransfer(
-    ERC20 _token,
+    IERC20 _token,
     address _to,
     uint256 _value
   )
@@ -22,7 +22,7 @@ library SafeERC20 {
   }
 
   function safeTransferFrom(
-    ERC20 _token,
+    IERC20 _token,
     address _from,
     address _to,
     uint256 _value
@@ -33,7 +33,7 @@ library SafeERC20 {
   }
 
   function safeApprove(
-    ERC20 _token,
+    IERC20 _token,
     address _spender,
     uint256 _value
   )

contracts/token/ERC20/StandardToken.sol

@@ -11,7 +11,7 @@ import "../../math/SafeMath.sol";
  * https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md
  * Based on code by FirstBlood: https://github.com/Firstbloodio/token/blob/master/smart_contract/FirstBloodToken.sol
  */
-contract StandardToken is ERC20 {
+contract StandardToken is IERC20 {
   using SafeMath for uint256;
 
   mapping (address => uint256) private balances_;

contracts/token/ERC20/TokenTimelock.sol

@@ -9,10 +9,10 @@ import "./SafeERC20.sol";
  * beneficiary to extract the tokens after a given release time
  */
 contract TokenTimelock {
-  using SafeERC20 for ERC20;
+  using SafeERC20 for IERC20;
 
   // ERC20 basic token contract being held
-  ERC20 public token;
+  IERC20 public token;
 
   // beneficiary of tokens after they are released
   address public beneficiary;
@@ -21,7 +21,7 @@ contract TokenTimelock {
   uint256 public releaseTime;
 
   constructor(
-    ERC20 _token,
+    IERC20 _token,
     address _beneficiary,
     uint256 _releaseTime
   )

contracts/token/ERC20/TokenVesting.sol

@@ -15,7 +15,7 @@ import "../../math/SafeMath.sol";
  */
 contract TokenVesting is Ownable {
   using SafeMath for uint256;
-  using SafeERC20 for ERC20;
+  using SafeERC20 for IERC20;
 
   event Released(uint256 amount);
   event Revoked();
@@ -65,7 +65,7 @@ contract TokenVesting is Ownable {
    * @notice Transfers vested tokens to beneficiary.
    * @param _token ERC20 token which is being vested
    */
-  function release(ERC20 _token) public {
+  function release(IERC20 _token) public {
     uint256 unreleased = releasableAmount(_token);
 
     require(unreleased > 0);
@@ -82,7 +82,7 @@ contract TokenVesting is Ownable {
    * remain in the contract, the rest are returned to the owner.
    * @param _token ERC20 token which is being vested
    */
-  function revoke(ERC20 _token) public onlyOwner {
+  function revoke(IERC20 _token) public onlyOwner {
     require(revocable);
     require(!revoked[_token]);
 
@@ -102,15 +102,15 @@ contract TokenVesting is Ownable {
    * @dev Calculates the amount that has already vested but hasn't been released yet.
    * @param _token ERC20 token which is being vested
    */
-  function releasableAmount(ERC20 _token) public view returns (uint256) {
+  function releasableAmount(IERC20 _token) public view returns (uint256) {
     return vestedAmount(_token).sub(released[_token]);
   }
 
   /**
    * @dev Calculates the amount that has already vested.
    * @param _token ERC20 token which is being vested
    */
-  function vestedAmount(ERC20 _token) public view returns (uint256) {
+  function vestedAmount(IERC20 _token) public view returns (uint256) {
     uint256 currentBalance = _token.balanceOf(this);
     uint256 totalBalance = currentBalance.add(released[_token]);