fix bugs from moving things to xsec.py

  Also changed colors of debug plots in fitBiasStudy.py
setup H->gg bias measure in xsec.py and fitBiasStud.py

  xsec.py: bias numbers for Group 3 (including bernstein) biases
  singleUseScripts/biasEnvelope.py setup to read in Hgg-style bias file