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
Merge pull request #11 from roger-wolf/master

making script executable
fix indices and names
Revert "support for new naming scheme" to have the branch based on
what's in the production repository

This reverts commit 00f7eeeda799e26b0a5c8eb70b3eb60f55f56ab8.
Revert "Pre and post fit shapes and uncertainties" to go back
to the central master branch

This reverts commit 2caf3b06d028ea85aeb3d4d97eb5933c652d846c.