Update ModelTools.py

When there are sigmaL and sigmaR there is no sense trying to get sigma: it won't be there.
Update AsimovUtils.cc

Added RooBifurGauss to the possibilities.
Merge pull request #4 from adavidzh/master

Fixed asym param usage
Create README.md
fixed include guard

was conflicting with RooFits RooExponential.h (see cms-analysis/HiggsAnalysis-CombinedLimit#5 )
Merge pull request #6 from andreh7/ah-2013-07-05

fixed include guard to avoid conflict with RooFit proper.
Added QCD running of quark masses.
Merge pull request #8 from adavidzh/master

Running masses
commiting changes to use RooMultiPdf -> discrete nuisances
updated HZZ4LRooPdfs.cc with new RooaDoubleCBxBW
updated HZZ4LRooPdfs.h with new RooaDoubleCBxBW
Merge pull request #9 from msnowball/master

Updated HZZ4LRooPdfs.h/cc
Normalised lib name usage for cross-platform compatibility
Constructor directly from file
Merge pull request #10 from adavidzh/master

Constructor directly from file
making script executable
Pre and post fit shapes and uncertainties
support for new naming scheme
Merge pull request #11 from roger-wolf/master

making script executable
fix indices and names