Change intrinsic camera matrix initialization

In the function cvInitIntrinsicParams2D the principal point for
normalized image coordinates is set to 0/0. This updates the function
to initialize the principal point at 0.5/0.5.
ocl: workaround for ProgramCache cleanup issue, use RAII to print kernel build error
ocl: fix FFT initialization
OpenCL examples refactoring
Merge pull request #1658 from alalek:ocl_fixes
Fixed incorrectly unprefixed constant names in the OpenNI tutorial.

Bug report: http://code.opencv.org/issues/3329
Merge pull request #1666 from SpecLad:cv-cap-openni
Merge pull request #1649 from asandwhich:2.4
Merge pull request #1659 from ilya-lavrenov:ocl_examples