added docs for validation crowdsales

contracts/crowdsale/validation/CappedCrowdsale.sol

@@ -3,16 +3,25 @@ pragma solidity ^0.4.18;
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
 
+/**
+ * @dev Crowdsale with a limit for total contributions
+ */
 contract CappedCrowdsale is Crowdsale {
   using SafeMath for uint256;
 
   uint256 public cap;
 
+  /**
+   * @param _cap Max amount of wei to be contributed
+   */
   function CappedCrowdsale(uint256 _cap) public {
     require(_cap > 0);
     cap = _cap;
   }
 
+  /**
+   * @return Whether the cap was reached
+   */
   function capReached() public view returns (bool) {
     return weiRaised >= cap;
   }

contracts/crowdsale/validation/IndividuallyCappedCrowdsale.sol

@@ -4,20 +4,35 @@ import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
 import "../../ownership/Ownable.sol";
 
+/**
+ * @dev Crowdsale with per-user caps
+ */
 contract IndividuallyCappedCrowdsale is Crowdsale, Ownable {
   using SafeMath for uint256;
 
   mapping(address => uint256) public contributions;
   mapping(address => uint256) public caps;
 
+  /**
+   * @param _beneficiary Address to be capped
+   * @param _cap Wei limit for individual contribution
+   */
   function setUserCap(address _beneficiary, uint256 _cap) external onlyOwner {
     caps[_beneficiary] = _cap;
   }
 
+  /**
+   * @param _beneficiary Address whose cap is to be checked
+   * @return Current cap for individual user
+   */
   function getUserCap(address _beneficiary) public view returns (uint256) {
     return caps[_beneficiary];
   }
 
+  /**
+   * @param _beneficiary Address of contributor
+   * @return User contribution so far
+   */
   function getUserContribution(address _beneficiary) public view returns (uint256) {
     return contributions[_beneficiary];
   }

contracts/crowdsale/validation/TimedCrowdsale.sol

@@ -3,12 +3,19 @@ pragma solidity ^0.4.18;
 import "../../math/SafeMath.sol";
 import "../Crowdsale.sol";
 
+/**
+ * @dev Crowdsale accepting contributions only within a time frame
+ */
 contract TimedCrowdsale is Crowdsale {
   using SafeMath for uint256;
 
   uint256 public startTime;
   uint256 public endTime;
 
+  /**
+   * @param _startTime Crowdsale opening time
+   * @param _endTime Crowdsale closing time
+   */
   function TimedCrowdsale(uint256 _startTime, uint256 _endTime) public {
     require(_startTime >= now);
     require(_endTime >= _startTime);
@@ -17,6 +24,9 @@ contract TimedCrowdsale is Crowdsale {
     endTime = _endTime;
   }
 
+  /**
+   * @return Whether crowdsale period has elapsed
+   */
   function hasExpired() public view returns (bool) {
     return now > endTime;
   }

contracts/crowdsale/validation/WhitelistedCrowdsale.sol

@@ -3,18 +3,31 @@ pragma solidity ^ 0.4.18;
 import "../Crowdsale.sol";
 import "../../ownership/Ownable.sol";
 
+/**
+ * @dev Crowdsale in which only whitelisted users can contribute
+ */
 contract WhitelistedCrowdsale is Crowdsale, Ownable {
-  
+
   mapping(address => bool) public whitelist;
 
+  /**
+   * @param _beneficiary Address to be added to the whitelist
+   */
   function addToWhitelist(address _beneficiary) external onlyOwner {
     whitelist[_beneficiary] = true;
   }
 
+  /**
+   * @param _beneficiary Address to be removed to the whitelist
+   */
   function removeFromWhitelist(address _beneficiary) external onlyOwner {
     whitelist[_beneficiary] = false;
   }
 
+  /**
+   * @param _beneficiary Address to check whether already in the whitelist
+   * @return Whether the address is whitelisted
+   */
   function isWhitelisted(address _beneficiary) public view returns (bool) {
     return whitelist[_beneficiary];
   }