Implemented interface to NxM clusterizer

Implemented interface to NxM clusterizer
 - 5x5 can be activated using AliEMCALRecParam::SetClusterizerFlag(AliEMCALRecParam::kClusterizerNxN+1);
   - It would be better to create the corresponding enums in AliEMCALRecParam which I did not dare to do
   - Can be done once we know which version should be run in reco
 - Fixed access to OCDB. Previous versions would always load OCDB objects for run number 0 for the first file
 - Fixed memory lead due to copyously instantiated clusterizer
 - Only set path to OCDB if desired ("raw://" still is default)