Barron Optical Flow Techniques code

Updated C code horn.c, lucas.c from the J.L. Barron 1994 article “Performance of Optical Flow Techniques” that can easily compile with today’s compilers.

https://dx.doi.org/10.1007/BF01420984

https://www.cs.toronto.edu/~fleet/research/Papers/ijcv-94.pdf

Optical Flow field