Prep for removing CombineTools and CombinePdfs from repo

 * Move progs using CombineHarvester from HiggsTauTau to CombineTools
 * Copy Core/interface/Plotting*.h headers into CombineTools - unavoidable to have two copies of these. Also updated includes in all relevent CombineTools code to point to these
 * Added the improved OpenFromTFile method to FnRootTools from TFileIO
Delete CombineTools and CombinePdfs
remove CombineTools from Doxyfile
try and fix compile error in 53X
slight css tweak
Merge pull request #13 from ajgilbert/remove-combine-tools

Remove CombineTools and CombinePdfs from the framework - migrate to HTT limits package