Added proper testing of the end of quicktime video files.

CvCaptureFile::grabFrame() always returns 1 regardless, which causes
dead loop when relying on the return value of VideoCapture::read().
Removed trailing whitespace in cap_qtkit.mm.
added CV_16SC2 && CV_16UC1 map types support to ocl::remap (INTER_LINEAR mode)
added ROI support to ocl::buildWarp*Maps functions
added an accuracy test for ocl::buildWarpPerspectiveMaps
fixed ocl::cvtColor for CV_YUV2BGRA and CV_YUV2RGBA
added YCrCb to RGB, BGR, RGBA, BGRA modes to ocl::cvtColor
color.cpp refactoring: created generic interface for toRGB and fromRGB callers
added RGB -> XYZ conversion to ocl::cvtColor
added XYZ to RGB conversion to ocl::cvtColor
Fix the build of OpenCV with XIMEA on Windows 64 bits:
  - crosses initializations in "cap_ximea.cpp" (which also contained some awfull "goto" instructions)
  - the "CMAKE_CL_64" variable is not initialized when using mingw

PR#1039 modified to be able to merge on branch 2.4
added RGB[A] <-> BGR[A] conversion to ocl::cvtColor
replaced custom PI by OpenCL M_PI constant
Make Integral sum support cv_32f, sqsum support cv_64f.
fix warning.
Trailing whitespace removal.
added RGB5x5 <-> RGB conversion
Merge pull request #1780 from ilya-lavrenov:ocl_m_pi
added a performance test for ocl::buildWarpPerspectiveMaps; moved warps to a separate file
Fixed the "image sequence" capture not failing when a pattern isn't found.

at can't be a null pointer, so the condition was always false, and
a nonsensical pattern like "image.png%00d" was being inferred.