(1) PairlistDistance is properly passed on to ComputeForce objects;
  (2) Power of 2 threads are now used in particle-grid force reduction;
  (3) Fixed accidental transpose of threads and blocks in grids' particleList kernel call

Fixed bug where pairlistDistance in Confugration.cpp was not being used; problem still remains where CellDecompoisiont ignores pairlistDistance; added IMD forces

Fixed bugs in initialization of Exclusions and in the calculation of forces due to angle potentials . Added coordinate file for RBs. Added normalization of orientation in RB integrator.

Implemented "particleLists" for rigid body--particle interactions; made RigidBodyType class manage its own device data for particle interactions

Fixed issues with coordinate wrapping during integration; improved implementation of select matrix operations

Added logic to angle code to avoid singularity; improved tabulated bonded kernel arguments; commented out (non-working) get_energy code