Ethereum: Utility function for EIP-721 (non-fungible tokens)

[jornfranke]

EIP-721 has been created in spirit of EIP-20, but focuses on non-fungible tokens. This allows you to trade a huge variety of assets on the Ethereum blockchain, such as physical properties, virtual collectables or negative value assets (loans, burdens etc.).

The goal of this utlity function is to facilitate analysis on those standardized types of tokens.
Includes unit tests and example application.

[jornfranke]

https://github.com/ethereum/EIPs/blob/master/EIPS/eip-721.md
and
https://github.com/ethereum/EIPs/blob/master/EIPS/eip-165.md