added a comparison of the recoil Pt to RichBOS (histogram 10di)
added two methods:

integrateGraph(TGraph* graph, int first=0, int last=-1)

scaleGraph(TGraph* graph, float scale=1, int first=0, int last=-1)

to respectively get the integral and normalize a TGraph.
Theese methods are not yed contained in the obsolet ROOT4STAR
Now the Z0 selection is almost done and the Z0 four vector calculated.