when promoting a nuisance to a POI, it should be removed from the nuisances (important if one is running with -S 0)
some control for the optimizations when not using our NLL
Vectorized RooCBShape, with different possibilities (sorted or
unsorted datasets, fast or slow math functions).
Sizeable speedup on ATLAS H->gg workspace.
Merge pull request #140 from gpetruc/slc6-root5.34.17

SL6:  code improvements for LHC combination