Convert code base to work with CUDA

[nLevin13]

https://docs.opencv.org/3.4/d1/d1a/namespacecv_1_1cuda.html

[nLevin13]

Use cuPy, runs numpy on cuda; very slow, unusable results

• parallelizing Cython code (am currently facing issues with GIL, will try to convert code to pure C arrays to avoid the issue)
• Convert repetitive code to for loops for easier parallelization
• Convert pythonic code to static typed numpy arrays for better C performance
• Profile current code to find other areas for performance improvement.