E0d/specify coffee sources

@cpennington 
@singingwolfboy 
@ormsbee 

Because we were pulling in all coffee files under edx-platform, this means we are occasionally compiling things in build that come from pypi packages.  There's a definite incompatibility with coffee in the pygment source and our version.  This was breaking on dev-edxapp-002 which was the victim of an aborted deploy.  I think this was a likely cause of some of these issues:

https://groups.google.com/forum/#!msg/edx-code/S9jHLu3MMNY/Ztl3QOdPWVEJ

*I haven't tested on a Mac*