added ENV variable CLANG_VERSION to travis config
Merge pull request #109 from kreczko/fix-travis

Fixing travis builds - clang version
Fixes to the log likelihood calculation
 - changed N_total to N_max
 - changed data_i to v_data
 - changed data_term to data_i
 - deployed Emyr's fix for the log likelihood calculation
Merge pull request #108 from kreczko/fix-likelihood

Fixes to the log likelihood calculation
Fixing typos
Updating configuration
Commenting out PDFs and fit results producers for ttbar generator systematics
Adding proper hadronisation uncertainty (powheg-herwig - powheg-pythia) and pt reweighting
Added PDF systematics, removed ptreweight systematic