template: use matrix for 90%eff operating point
switch back to scale factors for 90% eff./python/buildWeightedMatrix.py
buildRatio: refactor buildPercentages*, keep track of counts as well
label the fractions with their counts
buildMatrix: plotFractions addl arg
trick to plot fractions also in extraction regions
label count/region rather than count/region/sample
plotFractions: add the count label only when counts are available (anyway we would need raw counts...)