1. set your hydra environment (defall.sh of your hydra)
2. set your input + output file in TreeAnalysis.cc
   inputfile: root file produced by HQAMaker (contains 
   a tree of QA objects with informations per file.
   Multiple file can be merged by using hadd to one file before
   or added as single files to the chain.
   outputfile: contains histograms of variables as function
   of the runid
3. compile:   
      a. setup Makefile to fit to the hydra version       
      b. make clean build install
4. run:  ./TreeAnalysis