Added few opencl optimizations (as Intel platform codepath):

1. HaarDetetctor: repack nodes to reduce memory footprint
2. cornerMinEigVal: 4 ocl kernels are fused into 1 for sobel calculation
try to fix build error
try to made compatible with mac
fix CUDA 5.5 support (npp, arm cross compilation) in CMake scripts:

The patch was submitted to CMake and might be available
in the next CMake release.

But until we have the fix in CMake we should add workaround in our scripts.
rename imageproc_sobel2.cl -> imageproc_sobel3.cl for consistency
fix bugs on host and device sides for imgprog_sobel3.cl
added own version of FindCUDA.cmake
Merge pull request #1670 from jet47:cuda-cmake-fix
Fix a typo
fixed find package CUDA for cross-compilation

replaced find_host_package with find_package and
set CMAKE_FIND_ROOT_PATH_MODE_LIBRARY to BOTH, because NEVER 
doesn't work for CUDA_CUDA_LIBRARY, which is located in 
/usr/arm-linux-gnueabihf/lib/libcuda.so for ARM
Merge pull request #1713 from pengx17:patch-2
Merge pull request #1675 from krodyush:opencl-optimization
Merge pull request #1714 from jet47:find-cuda-fix
ocl: split: update tests and implementation