Opencv_contrib: Feature request: Cuda CLAHE for 16 bit images

[isra60]

non CUDA version offer support for 16 bit images. Could be possible to add the same support to CUDA version??

[nglee]

@alalek May I work on adding this feature?

[alalek]

@nglee Yes

[isra60]

That will be great. I have been trying with this but I found a few problems like the amount of shared memory neccesary for a histogram of 16K values instead of 256.