Give cv::ocl::CLAHE a virtual destructor, for the usual reasons.
Fix a bug of convertTo.
The bug was found that all 3-channel oclMat's were converted to
4-channel oclMat's after using convertTo function.
Add a workaround to interpolate between oclMat and Input/OutputArray.
Revise naming for getOclMat function.
Merge pull request #1031 from pengx17:2.4_fix_converTo
Merge pull request #1034 from pengx17:2.4_oclmat_inoutarray
Merge pull request #1028 from SpecLad:ocl-clahe-dtor