- new reduce implementation (with kepler optimizations)
- saturate_cast via asm command
- video SIMD instructions in element operations
- float arithmetics instead of double
- new deviceSupports function

- fixed printCudaDeviceInfo for new CC
- fixed some compilation errors and warnings
- removed unset command from CMake script
- removed unused std imports

used random images in gpu filter tests

added PyrLKOpticalFlowDense performance test

added convert functions to BruteForceMatcher_GPU
other minor fixes

fixed BFM warning ("cannot tell what pointer points to")

minor optimization of SURF_GPU (reduce memory transfers, use structure of arrays instead of array of structures)

temporarily disabled compute descriptor kernel for new cards (some problems with threads synchronization), old version of kernels is used.