Add support for CHARMM

CHARMM (Chemistry at HARvard Macromolecular Mechanics) is a versatile
and widely used molecular simulation program with broad application to
many-particle systems.

This is a non free program. You need to buy a license to obtain the
source code.
CHARMM: fixed small errors in easyconfigs
CHARMM: updated to remarks in PR
CHARMM: remove g09 dep
CHARMM: updated build options to new easyblock

We now use a string instead of list.
Merge pull request #584 from wpoely86/charmm

Add support for CHARMM