cosmic digitizer parameters within the mixing module
fix priority for injection
Merge pull request #6400 from boudoul/cosmic_configmixingfor72X

cosmic digitizer parameters within the mixing module
Merge pull request #6424 from boudoul/prio_72X

fix priority for injection
Merge remote branch 'origin/CMSSW_7_2_X' into CMSSW_7_0_X