Use LINK_RT everywhere
Build modules instead of shared libs for py on Mac

Prefix compiled files with underscore
Autodetect Numpy
Merge pull request #110 from vene/macos

[WIP] MacOS build
Thanks vene for the time you spend for geting it runing under macos.
The reported bug seemed to be a problem with sphinx-build and not with opengm - if I understand it correctly.
On a 'older' machine I had problems with sphinx-build, too. We will verify if we have the same problem too and how it can be fixed.