CMAP support

[vedranmiletic]

ff19SB supports (per-amino-acid) CMAPs, but cpptraj doesn't print their energies. It would be nice to have them supported, just like other bonded interactions are.

To give credit where it's due, this issue was also brought up in #842 that has since been closed.

[drroe]

This is a good idea, and one that has been on my agenda for a while. I actually have a branch that does an overhaul of how topology information is processed and handled (https://github.com/drroe/cpptraj/tree/prepareforleap.remote.buildatom) that I want to get merged into the master branch before adding this support, but recent upheavals at my current place of employment over the past few months have slowed by research/coding efforts dramatically.

I'm currently traveling, but I will make a concerted effort next week to try and get this code merged, or at the very least get some kind of minimal support for CMAP term energies. Thanks for bringing it back to my attention!