removed cert checking when downloading external packages

- could fail if certificate unknown -- but should not really worry us anyway
Fixed bugs in the geo description of FEI4Single and added FEI4Double
Fixed bug in hitmaker two
fixed documentations error in fei4double
Renamed variables, fixed syntax, removed obsolete includes in EUTelProcessorGeometricClustering
Removed namespace pollution
Introducing individual sparse clustering algo
Fixed bug in new sparse clustering stand alone processor
Merge pull request #73 from tbisanz/head

Added FEI4Double and minor Bugfix in EUTelHitMaker__Two__
Merge pull request #75 from tbisanz/clustering

Updated geoemtric clustering and introduced standalone clustering processor
Merge remote-tracking branch 'eutelescope/master' into merged_newGEAR_newGeoPropagator