Conflicts:
	CMakeLists.txt
	modules/calib3d/src/calibration.cpp
	modules/ocl/src/cl_programcache.cpp
	modules/ocl/src/filtering.cpp
	modules/ocl/src/imgproc.cpp
	samples/ocl/adaptive_bilateral_filter.cpp
	samples/ocl/bgfg_segm.cpp
	samples/ocl/clahe.cpp
	samples/ocl/facedetect.cpp
	samples/ocl/pyrlk_optical_flow.cpp
	samples/ocl/squares.cpp
	samples/ocl/surf_matcher.cpp
	samples/ocl/tvl1_optical_flow.cpp

changed InputArray's enumeration constant for UMat, since it may potentially conflict with existing OpenCL module. refactored Kernel's setArg API (now UMat is passed to a kernel as a structure, as Alexander A suggested). removed Kernel's cleanup callback from the external API; now each kernel keeps track of used matrices and they are dereferenced after it's complete.

The reasons for that are twofold:

1) LINK_PRIVATE is only available since CMake 2.8.7.
2) The way it was used generated a warning because of CMake policy CMP0023:

   http://www.cmake.org/cmake/help/v2.8.12/cmake.html#policy:CMP0023

Using LINK_INTERFACE_LIBRARIES actually causes another warning - this time
because of CMake policy CMP0022:

   http://www.cmake.org/cmake/help/v2.8.12/cmake.html#policy:CMP0022

I set the policy to OLD, because NEW means subtle changes when compiling
with CMake 2.8.12, and I don't want to research that this close to release.
:-)

I also removed the setting of CMP0003, because it's set by
cmake_minimal_version anyway.

It was actually acting as an additional argument, breaking the error message.

fixed some bugs in OpenCL branch of UMat implementation; maybe now the tests will finally pass?! (please ;( )

Linker dependencies to all OpenCV modules are invalid.
We should not include other bindings in this list (like "opencv_python").