rewrite gpu/device/vec_math.hpp file 

old version isn't compiled with CUDA 5.5
new version doesn't depend on functional.hpp
fixed BroxOpticalFlow regression test

the output of BroxOpticalFlow differs a bit in CUDA 5.5
fixed BoxFilter sanity test (different rounding results)
fixed BroxOpticalFlow sanity test (increase epsilon value)

+ interpolateFrames and createOpticalFlowNeedleMap
Merge pull request #948 from jet47:cuda-5.5-support