Minor standards and cleanup additions.

Add docs for DelayedClaimable

feat: remove yarn in favor of npm

fix: make SplitPayment payable by default

Address new compiler warnings

Minor formatting change

Update to truffle 4.0.0 and solc 0.4.18

This is required to update to truffle 4 and solc 0.4.18, see PR #573

had to up the gasLimit in test.sh to avoid an out of gas error when deploying the scripts

Create CappedToken, a capped MintableToken

Small code style change

Fix unused variable warning in `Standard Token.sol`