[VestedToken] Check if tokens can be transferred on transferFrom

Add clarifying comment to standard token transfer from function

solidity version 0.4.8

Added a contactable contract

Update modifiers to throw and update corresponding tests

Update modifiers so that they fail "loudly" by throwing errors rather then silently no-oping. Updated tests to remain compatible with these changes

Refactor in preparation for audit

Aragon new collaborating organization

Vested Token implementation (Standard Token with vesting calendar)

Vesting test fixing help