Merge pull request web3swift-team#210 from matter-labs/develop

2.2.1

Merge pull request web3swift-team#179 from matter-labs/develop

2.2.0

Merge pull request web3swift-team#175 from matter-labs/develop

2.1.6

Merge pull request web3swift-team#170 from matter-labs/develop

2.1.4

Merge pull request web3swift-team#169 from matter-labs/fixTravis

Fix travis

Merge pull request web3swift-team#152 from matter-labs/develop

2.1.3 fix No2

Merge pull request web3swift-team#141 from matter-labs/develop

Swift 5 update

Merge pull request web3swift-team#132 from dexon-foundation/develop

let some functions public for customization

Merge pull request web3swift-team#124 from matter-labs/develop

2.1.0

Merge pull request web3swift-team#95 from matterinc/2.0

introduce a fix for invalid value in gas estimation, call and send transactions