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
workaround for cv::multiply bug
moved to relative errors in ocl::norm tests
fixed an accuracy test for ocl::resize (in some cases dsize.area() was equal to 0)
fixed ocl::copyMakeBorder
Merge pull request #1669 from ilya-lavrenov:ocl_copyMakeBorder
Merge pull request #1672 from ilya-lavrenov:ocl_arithm
Merge pull request #1673 from ilya-lavrenov:ocl_norm
Merge pull request #1676 from ilya-lavrenov:ocl_resize_test
Rewrite distanceToCenters.
It supports NORM_L1 distance types now and can
use user provided indices.
Also fixed a bug of kmeans where distance pointers should be float instead
 of double.

NORM_L2 changed to NORM_L2SQR, Accuracy and Perf tests are added

added ROI support in accuracy test of distanceToCenters