class TQSampleInitializer: public TQSampleVisitor, public TQSampleInitializerBase

 TQSampleInitializer:

 A simple sample initializer, capable of traversing a given sample folder structure,
 locating the nTuples in the form of ROOT files an TTrees contained therein.

 This simple initializer variant has two means of determining the correct file path:
 - the ".xsp.filepath" tag which might be set on the individual sample
 - the file system directory announced to the initializer via readDirectory
 this variant will use the sample name in conjuction with the
 "filenamePrefix" and "filenameSuffix" tags to find the sample root file

 Additionally, the tree name is automatically determined with the following method
 - the file is opened and any objects inheriting from TTree are investigated
 - their names are compared to the tag "treeName" (default: "*" unless specified differently
     by the tag with key "treeName" set on the initializer)
 - if there is exactly one match, the initializer proceeds.
 - in the case of zero or multiple matches, it will terminate with an error.

 After the tree name has been determined, the number of events is retrieved from
 the tree. In conjunction with the luminosity (can be set as "luminosity" tag on any
 parent folder of the sample or the sample itself, as well as on the initializer)
 and the tags "kfactor" and "filtereff" on the sample, it is used to set the sample
 normalization.