Add command-line options for fast/no-threshold centrality and for num of mkl threads.

Signed-off-by: Zarrar Shehzad <czarrar@gmail.com>
clean up of centrality testing files

Signed-off-by: Zarrar Shehzad <czarrar@gmail.com>
properly call centrality functions from calc_centrality

Signed-off-by: Zarrar Shehzad <czarrar@gmail.com>