support/algorithms: Bugfix for Infomap weighted
bulk: small improvements
commstats: improve formatting

- Can specify legend kwargs.
- Can specify plotstyle and color by mapping.
commstats: log_bin: force integer bin for k<minlog
commstats: rename Density to CmtyDensity, exclude self-loops
ioutil: read_any: read edgelists as weighted
test_algorithms: Add weighted tests
commstats: Add pickling support to Statter

- lambda functions in self._data collections.defaultdict were not
  pickleable.
commstats: Add documentation and comments