New raw ratio plotting script
Variable binning for raw ratios (commented out)

Commented out for the moment as it looks horrible.  The idea is to
dump binning scheme with python/dump-var-bins.py, read and apply in
python/raw-ratios.py.

Also switch to creating histogram yourself (rootpy.plotting.Hist)
instead of relying on the 'expr>>hist' syntax used by TTree::Draw().
Clean-up and clearer axis labels for raw ratios