Sig syst

Hello Ted,

This branch implements the capability of reading the signal systematic uncertainties from a root file.  The root file is assumed to be present in the ra1e directory corresponding to the signal efficiency one is running over.

The major change is the fact that effUncRel needs to be defined per category.  To accommodate this, workspace had to modified.  
  
I've implemented a switch in configuration/signal.py to keep things backwards compatible. 

Y.