Port to OSX

[bgribble]

In fooling around with this on my work Mac I have found that recent "brew" installable packages for GObject and Clutter seem to be importable from gi.repository, which was sort of my litmus test for when it was worth devoting any time to getting MFP to run on OSX.

I'm able to get all the way through waf configure and most of the way through waf build without really making any changes.

To get the rest of the way through the build, I'll need to:

• Make ALSA an optional dependency
• Document the packages needed to do the build
• ???