MT2 updates and validation

Things of general interest:
1) write output in the CERN EOS
2) added private T2tt-T2bb-T2qq sample 
3) added class to apply recoil corrections
4) speed up a bit the IsoTrackModule
5) commented the default tkMET and QG since are time consuming

MT2:
1) added validation script
2) updated mindPHI (eta range) and Zinvp4
3) added friend tree for kinematic variables 
4) cleaned up MT2 calculation file