[Dcmlib] Integration of GDCM 0.6 into ITK

[Mathieu Malaterre]

Hello,

	The integration of GDCM is done in ITK CVS Head. For those of you using 
an external gdcm build, you'll have a build problem since I rename 
libgdm into libitkgdcm.

	In order to use it you have to turn the USE_GDCM to ON in your ITK 
configuration. Again for those who were using outside gdcm, remove all 
old GDCM references.

	Since the gdcm library I put into ITK is the 0.6 I would like to remove 
any backwrad compatibilty (for instance to gdcm 0.5) that are currently 
in itkGDCMImageIO and itkGDCMSeriesFileNames.

	Please note this support is now very experimental. In particular gdcm 
was relying on the 'tellg' fonction which is broken on some plateforms. 
In the next days, I'll use more and more of kitware 'cross plateform' 
fonction to work around known plateforms bugs. Therefore the 
developement of gdcm and the gdcm within ITK will differ as I will have 
access to kwsys and other library which I didn't from gdcm only.

Let me know if you have any problem,
Mathieu