Implement ERC721 For Encapsulating Art Generated by Artonomous

[simondlr]

Each Art piece auctioned by Artonmous contains two core components that define it's unique identifier:

• the hash used to generate its art.
• the blockhash at the start of the auction.

[simondlr]

Consensys/Tokens#130
https://github.com/OpenZeppelin/openzeppelin-solidity/blob/master/contracts/token/ERC721/ERC721Token.sol

[simondlr]

Added already.