[Dcmlib] pixel data OpenGL compatiable

[Aris Basic]

what i woudl like to see in gdcm is the way to get pixeldata from dicmo
iamge in such fashion that is 100%
compatible with opengl (for loading a 2D texture or just as pixels).

That would have to enforce some conversions (12bit packed into 16bit
would have to be ajusted)
signed images (pixeld ata needs to be ajusted [using openGL signed types
doesnt work ] ).

Also a method of getting Patient/Image orientations as A,P,R,L,...
values instead of dicom cosines would be nice too :)

Aris