Some notation in testcases changed.
Merge remote-tracking branch 'georg/Merged_EK' into Merged_EK

"Only the object_in_fluid_gpu testcase does not work."
Worked on object-in-fluid problem, not fixed yet, however.
Played with the back transform from rho, j, phi to populations, but did not manage to fix the problem. The back conversion is definitely the culprit, in both the LB and the LB_GPU. Also removed some warnings and made some minor style changes.
Fixed bug in output of the values returned by calc_mesoscopic_quantities_in_MD_units
Fixed the pressure, fixed setting the velocity on a specific node, and the testcases work properly.
Forgot to add one file in previous commit.