Convert support files in gmxana to C++

Renamed symbols using reserved C++ names, and removed geminate
and ballistic code paths that just resulted in GROMACS errors
messages about missing code when they were called. Unused parts
of gmx_hbond have been cleaned up according to comments from
Erik Marklund.

Change-Id: I925b1b5ca4a8420e0c8a38ca99f56361359d713b