Log message:
Import mcl-12-135 as wip/mcl.

The MCL package is an implementation of the MCL algorithm, and offers
utilities for manipulating sparse matrices (the essential data structure in the
MCL algorithm) and conducting cluster experiments.

MCL is currently being used in sciences like biology (protein family detection,
genomics), computer science (node clustering in Peer-to-Peer networks),
and linguistics (text analysis)