Add some comments about

Add some comments about
   // Description:
   // Aware user is allowed to pass his own gdcm::File *, so he may set *any Dicom field* he wants.
   // (including his own Shadow Eleents, or any gdcm::SeqEntry)
   // gdcm::FileHelper::CheckMandatoryElements() will check inconsistencies, as far as it knows how.
   // Sorry, not yet available under Python.
vtkSetMacro(GdcmFile, gdcm::File *);

and

   // gdcm cannot guess how user built his image (and therefore cannot be clever about some Dicom fields)
   // It's up to the user to tell gdcm what he did.
   // -1) user created ex nihilo his own image and wants to write it as a Dicom image.
   // USER_OWN_IMAGE
   // -2) user modified the pixels of an existing image.
   // FILTERED_IMAGE
   // -3) user created a new image, using existing a set of images (eg MIP, MPR, cartography image)
   //  CREATED_IMAGE
   // -4) user modified/added some tags *without processing* the pixels (anonymization..
   //  UNMODIFIED_PIXELS_IMAGE
   // -Probabely some more to be added
   //(see gdcmFileHelper.h for more explanations)

   void SetContentTypeToUserOwnImage()         {SetContentType(VTK_GDCM_WRITE_TYPE_USER_OWN_IMAGE);}
   void SetContentTypeToFilteredImage()        {SetContentType(VTK_GDCM_WRITE_TYPE_FILTERED_IMAGE);}
   void SetContentTypeToUserCreatedImage()     {SetContentType(VTK_GDCM_WRITE_TYPE_CREATED_IMAGE);}
   void SetContentTypeToUnmodifiedPixelsImage(){SetContentType(VTK_GDCM_WRITE_TYPE_UNMODIFIED_PIXELS_IMAGE);}