1.) QC code runs now even faster

1.) QC code runs now even faster

2.) 2D differential cumulants are back on track.

3.) Propagated error also to differential cumulants vs pt and vs eta

4.) New feature: Implemented histograms which quantify detector bias to differential flow, both vs pt and vs eta
    (You can find them in the QC output/Differential Flow/Results).

5.) Resolved issue with accessing modified common constants in Finish() (relevant for high-pt analysis)

6.) Fixed Coverity issues;