it is internal class, no need to export it

The deinitialization of BufferPool internal objects is controled by global
object, but it depends on other global objects, which leads to errors
caused by undefined deinitialization order of global objects.

I merge global objects initialization into single class, which performs
initialization and deinitialization in correct order.

it is generated by CUDA headers and we can't fix it

opencv_run_all_tests_unix.sh already exports OPENCV_TEST_DATA_PATH

(with this else-branch, argument contour2 would not be used at all)

the parameter variable.

It could improve the performance of
OCL_Cascade_Image_MinSize_CascadeClassifier.CascadeClassifier/*.
Especially,
OCL_Cascade_Image_MinSize_CascadeClassifier.CascadeClassifier/15
OCL_Cascade_Image_MinSize_CascadeClassifier.CascadeClassifier/16
could be improved about 2% in Intel platform.
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

It should also be better for optimizing when compiling kernel.
Signed-off-by: Yan Wang <yan.wang@linux.intel.com>

Changed CV_DbgAssert to CV_Assert when setting video modes for OpenNI2. Otherwise, in release mode the default modes never get set

sensors which do not have image generators.