Notes from Damian about these files

Down to the simplest systems for tests and any necessary
reparameterizations.

All of these systems are composed of single bonds between two atoms
and all other valences filled with Hydrogen.  The labeling scheme is
FragmentA_FragmentB.mmp/pdb with the two important atoms connected by
the "_".  In some cases, like H_X, the parameter is for the H-X bond.

Also notices a little import issue with the CAD side (it won't read
H2 as a connected system).  I'll bring that one up.

The double bond systems are mostly done.  There are a few problem
structures that nature never intended that, despite my wish to have
the exhaustive set, we maybe should intend either.  I'd hate to be
the guy proposing the structure at a board meeting arguing that the
existence of parameters means we've got a shot of making it.