[SVN revision 26470]
FIX (#5542): RGB colormaps with opacity supported now.

solution is still suboptimal since the level-window mechanism is precomputed for every voxel in the tensor- or qball-image. The mechanism should be realized in the 2D-image mapper to obtain decent speed and increase usability.

changes in picimage and 2D image mapper

Implemented opacity windowing in analogy to the intensity level window mechanism.

[SVN revision 26501]
FIX (#5542): moved level window mechanism to be performed mapper-internally. performance of previous method was not acceptable.

[SVN revision 26519]
FIX (#5542): GUI nicer

additional changes to the 2D image mapper to apply default properties

ready for checkin?

[SVN revision 26536]
FIX (#5542): implemented opacity level window for RGBA images

Missing check for NULL in ItkTypeID causes crash on RGBA images.

[SVN revision 27276]
FIX (#5542): Added check for existing itk type id in the image's pixeltype

[SVN revision 28542]
FIX (#5542): opacity level window for RGBA images