Codes required to do multiple hadronization and to print out cross section including HepMCFilter efficiency

The code change includes 

1) Josh's update which allows input lhe files to be hadronized multiple times in 
order to boost the matching/filter efficiency.

2) Eiko's update in GenXSectionAnalyzer, HadronizerFilter, and HepMCFilterDriver:
Additional GenFilterInfo with process name = "generator" is saved so to retrieve the filter efficiency of HepMCFilter and to compute cross section correctly.