improved load balancing with Verlet cut-off scheme

With the Verlet scheme the force calculation order is now like group:
non-bonded, bonded, PME
The non-bonded were done after PME, which prevented load balancing,
unless separate PME nodes were used.

Change-Id: I81588ac810ce7c022bd6809f29a19c41ba13449f
Merge "improved load balancing with Verlet cut-off scheme" into release-4-6