n-ary raid prototype using Reed-Solomon coding

calling ./raid [n] [m] [all files], where [all files] consists of n×m paths will overwrite the last m files with check data to reconstruct up to m of the n×m files in case of failure

calling ./raid [n] [m] [all files] [bad files], where [bad files] additionally consists of up to m of the paths in [all files] will write the reconstructed data to those files

test multiple [n] [m] combinations with ./fuzz.sh

see:
http://alamos.math.arizona.edu/RTG16/ECC/raid6.pdf
https://web.eecs.utk.edu/~jplank/plank/papers/CS-03-504.pdf
https://web.eecs.utk.edu/~jplank/plank/papers/CS-96-332.pdf