removed unset command from CMake script
fixed static build of gpu module with ffmpeg:

multiple definition of cap_ffmpeg_impl.hpp functions in gpu and highgui
moved block.hpp to include folder
speedup compilation of row_filter.cu and column_filter.cu

split them into several small files
add epsilon in sanity checks
sort for Hough sanity checks
fix abs_func and minimum/maximum functors
optimization for kepler
used float arithmetics in convertTo
added optimized deviceSupports function
element_operations.cu : used SIMD video instructions
added explicit unroll to reduce implementation
saturate_cast via asm cvt command
added common TransformFunctorTraits for element operations
fixed compilation for GCC 4.6
remove unused std imports
fixed warnings "double not supported"
temporarily disabled reduceKeyVal implementation for kepler

used fermi implementation
added more types support for gpu separable filters
removed type check in gpu::PyrLKOpticalFlow

not it support all depths