Refactor for a cleaner code, less is more in this regard!

[ProphetDaniel]

trafficstars

I made the following improvements:

• Added zeppelin-solidity.
• Use of zeppelin-solidity's Destructible rather than custom Killable.
• Cleaned 2_deploy_contracts.
• Deleted contracts/zeppelin/lifecycle/Killable.sol
• Deleted contracts/zeppelin/ownership/Ownable.sol

[apackin]

Looks like a good PR to me... Is this repo no longer being supported?