cleaned up calculateElectrostaticPairIxn for non-PME
cleaned calculateFixedElectrostaticsFieldPairIxn, non-pme
cleaned PME::calculateFixedElectrostaticsFieldPairIxn
initial cleaning of calculatePmeDirectElectrostaticPairIxn

   Removed perm. dipole/quadrupole from energy calculation
   force calculation currently disabled
Forces are consistent with previous implementation
removed comments. preserving torque and excluded forces
cleaned up/formatted PME direct pair interactions
added missing rr7 in PME force
Merge pull request #1 from gmedders/gm_pme2

Electrostatics cleanup by @gmedders