stable community detection

[wlwardiary]

c2g.py currently uses Graph.community_multilevel by Blondel et al, to split the giant cluster into smaller communities.

It might be useful to run different algorithms and compare the results.

[wlwardiary]

the following functions work reasonable fast:

• community_fastgreedy
• community_infomap
• community_label_propagation
• community_multilevel
• community_walktrap