first implementation for multiple hadronization attempts on lhe input plus hooks for additional HepMC level filtering at this stage and an example filter already useful for selecting JPsi->mu mu decays

Resolved Conflicts:
	GeneratorInterface/Core/interface/HadronizerFilter.h
fix weighting scheme for cases where jet matching and/or hadronization step can modify the weight
properly reset hadronization filter statistics
remove debug printout
Merged multipleHadronization_73x from repository bendavid
codes required to print out cross section correctly (including HepMCFilter efficiency
Merged eiko_73x_hepmcFilter from repository syuvivida
remove pythia6 dependency from filters
move HepMCFilters back into GeneratorInterface/Core and remove new package
add EOL's and remove commented code
Merge pull request #6319 from bendavid/multihadronization_core_73x

Multiple Hadronization
Merge remote branch 'origin/CMSSW_7_3_X' into CMSSW_7_0_X