Added converter sript which converts from DQM I/O format input root file, to histogram based DQM output file

Signed-off-by: Antanas Norkus <antanas.norkus@cern.ch>
Merge pull request #4737 from anorkus/DQMIO2histo_converter

DQMServices/FwkIO -- Added converter sript which converts from DQM I/O format input root file...
Merge remote branch 'origin/CMSSW_7_2_X' into CMSSW_7_0_X