Decide whether to do "framework" install for python and others on darwin or force a unix-style install

[cekees]

Here is some information on what os x frameworks are:

https://developer.apple.com/library/mac/#documentation/MacOSX/Conceptual/BPFrameworks/Concepts/WhatAreFrameworks.html

I had been building Python.framework for proteus because it's the "standard" way to build python on os x. I believe it still installs sym links into PREFIX/bin so it shouldn't complicate setting PATH. In the initial darwin-cek branch I did NOT do a framework build.