Honor multilib distributions when installing libraries

Created by: ozancaglayan

Hi,

Current build system installs shared libraries and pkgconfig files under /usr/lib but python site-package under /usr/lib64 on a multilib x86_64 distro like F17.

The correct directory is /usr/lib64 for both. I've created a patch for taking care of the library suffix using CMake. This also fixed nosetests and sphinx-doctest targets which were failing on the current tree on my system.

The patch is at: https://gist.github.com/4246783

Thanks!