Do not notify via Slack about PR build failures

fix docs issue #459 and align with README.md

Finish minting should be called only once

Update RefundVault.sol

improve mul performance and reduce gas cost

remove timer test helper

Create detailed ERC20 interface

Feature SplitPayment contract

Update TokenTimelock.sol: Issue #464

Add `npm init`

Fixes typos in documentation

Small typo fixes for bounty docs

Update SimpleToken.sol

Update ecrecovery.rst

Math.sol is not used, not needed

Add Slack notifications

Small thing, but the Math.sol is not really needed, since it is not used.

Use address(0) instead of 0x0

[TokenVesting] Add missing safemath ops

Multiple calls to `finishMinting` will emit multiple `MintFinished` events which may be surprising if one rely on `MintFinished` event.

Fix typo

[TokenVesting] vestedAmount should return the historical vested amount