Compatibility with pyScss 1.3, almost

[eevee]

This is what I came up with. It turns out your STATIC_URL hack does still work.

Still not done:

• Trying to compile /css/bar.scss doesn't work, just because Compiler.compile doesn't consult the search path; it assumes you're feeding it a regular filesystem path. This isn't terribly hard to fix; I'm just not sure what I want to do about it yet. Maybe a new Compiler entry point? But there are already a lot of those.
• The DEBUG toggle for only searching static files in prod mode was lost and hasn't been restored.
• I just remembered I didn't update setup.py, whoops!

Doing this has revealed some places that pyscss's extensibility is still pretty awkward. I'm not in any hurry to go change everything again, but suffice to say I might have to send you another PR come pyscss 2.0. API design is hard! Still, this is rather a bit better than before. :)

[rockymeza]

@eevee,

I can't work on this just yet, but I did take a quick glance at http://pyscss.readthedocs.org/en/latest/python-api.html and I'm liking what I see.

I will work through this pull request as soon as finish up some client work.

Thanks so much.

[rockymeza]

Hi @eevee,

I got this working with the Extensions interface.

It's released in 2.0.0.

Thanks so much for your help.