Made g_tune_pme work with 4.6 if user sets "-p" command line option

Added "-p" (performance statistics log file) to the list of files that
must not appear on the mdrun command line at launch time. (This would lead
mdrun to refuse to launch due to an unknown command line option.)

Change-Id: I268bbf6513709866b9a6a8d81c97706ccc832988
fixed GPU particle gridding performance issue

The scaling factor for the grid binning for the GPU pair search
was set incorrectly, which made the binning 50% slower.

Change-Id: I146592c37094a3d81a7ae50b3903fcc615e748d5