WIP: OS X port

This still needs work, I haven't been able to figure out yet what's going on with the prefix/root/home snafu in Python.  I'll take a deeper look at this later.

This should get people up and running on OS X.  I added some extra directives for homebrew, but this should be equally valid for other configurations.

I also updated the launcher commit.  If it would better to pull this out into a separate commit let me know and I'll adjust.