architectural changes to make dev easier
changed c func name
changed name: rank.mahal
Merge branch 'master' of https://github.com/markmfredrickson/optmatch into rank.mahalanobis
initial unit test for compute_rank.mahal
Merge from master. Preserve smahal.c and compute_rank.mahalanobis
Merge branch 'master' into rank.mahalanobis
Allow optmatch:::compute_rank.mahalanobis to be given as a method to match_on
Merge branch 'master' into rank.mahalanobis

Conflicts:
	R/match_on.R