Update for Top PAG Validation code
hltGetConfiguration: wrap list of input files longer than 255 elements
hltGetConfiguration: add an option to specify the parent input files or dataset
hltGetConfiguration: add a hilton-specific customisation
Merge pull request #6754 from fwyzard/hltGetConfiguration-improve-input

hltGetConfiguration: improve handling of input files and datasets (73x)
Merge pull request #6565 from ebouvier/UpdateNamesForTopValidationCode

Update for Top PAG Validation code
Merge remote branch 'origin/CMSSW_7_3_X' into CMSSW_7_0_X