support modern libqhull libraries

The module was renamed from 'qhull' to 'libqhull'
and therefore geometric_shapes fails to compile on up2date systems.

This commit adds a proper cmake test module for various qhull
versions (taken from pcl) and passes the detected version on
via a config file. That way the resp. correct headers are included.
Merge pull request #2 from v4hn/libqhull-support

support modern libqhull libraries