SerieHelper Normalization : stage 1

SerieHelper Normalization : stage 1
-------------------------
- Put as 'deprecated' the confusing method names GetFirstCoherentFileList(),
                                                 GetNextCoherentFileList()
      (the only 'cohenrence' they have is that they all have the same "Series
      Instance UID")
- Add less confusing method names GetFirstSingleSerieUIDFileSet,
                                  GetNextSingleSerieUIDFileSet().
The 3 following are not seen by end user :
- Replace the private attribute CoherentFileListHT by SingleSerieUIDFileSetHT
- Replace private typedef CoherentFileListmap by SingleSerieUIDFileSetmap.
- Replace iterator ItListHt by iterator ItFileSetHt

- Keep the public 'FileList' typedef, in order not to break the API
  (this -little bit- confusing name should be changed to FileSet : it's not a
   std::list, it's a std::vector; user don't care about it, but it's better to
   use meaningfull names)

SerieHelper Extention : stage 1
---------------------
 In the following stuff,  'XCoherent' stands for 'Extra Coherent',
  (The name 'Coherent' would be enough but it was used before;
  I don't want to put a bomb in the code)
  Any 'better name' is welcome !

 Add some methods, to split a 'SingleSerieUID' Fileset into 'Extra Coherent'
   FileSets.
   They return a std::map of Filesets (actually : std::vector of gdcm::File*)
   The key is the 'Orientation', the 'Position' or the 'Tag value'

   XCoherentFileSetmap SplitOnOrientation(FileList *fileSet);
   XCoherentFileSetmap SplitOnPosition(FileList *fileSet);
   XCoherentFileSetmap SplitOnTagValue(FileList *fileSet,
                                            uint16_t group, uint16_t element);

 Theese methods must be called by user, depending on what he wants to do, at
 application time.
 - *he* only  knows what his Series contain !-