fitBias: RooModelPlotter Debug plots

  RooModelPlotter: more label/legend control & can plot other fits
fitBiasStudy.py: can now output debug workspace

  now use debug bool to decide whether to output workspace and plots
fitBiasStudy: forgot .root ext when saving debug workspace
Merge branch 'master' into bernFixAParam

  merge in updated fitBiasStudy.py debugging
  output into bernFixAParam