Verlet branch not updating neighbor list

[orlandoacevedo]

The Verlet branch implements the Verlet Neighbor List, but overrides the simple cutoff. Needs to be integrated into the Master branch after proper integration.

Verlet does not seem to be updating the neighbor list. Short runs give correct energy relative to simple cutoff, but energy begins to deviate substantially as number of MC steps increase.

UPDATE:
It seems that the neighbor list is being updated in tests for different systems. Need to identify why the list is sometimes not updated.