Support multiple contracts in the same file

[tcoulter]

Truffle current expects you to separate all contracts into separate files, although that's not explicitly required by Solidity. See #86. That PR is now out of date with Truffle 2.0, but we should still support the feature.

Tasks:

• Ignore the file name and instead use the results of compilation to determine which contract abstractions (.sol.js files) to create.
• Remove requirement that there must be a contract within the .sol file that matches the file name.

[shayanb]

+1

[tcoulter]

This is done! Cheers!