+2004-06-24 Jean-Pierre Roux
+ FIX : - now Write drops LUT Descriptors and LUTs (if any)
+ when SamplesPerPixel =3
+ - now Write is no longer confused by
+ 'BitsAllocated = 12" and 'BitsStored=12"
+ ENH : - now gdcmHeader has its own Write methods
+ (in order to split the job that has not to be done
+ for gdcmDicomDir)
+