Up to v0.71

v0.65
- Adding Scale-Free generator from base graph
- Fixed edge-weight in importing from graphml where the edge weight does
not already exist.

v0.7
- Added local clustering coefficient. Picks 10% of nodes and expands to
one hop, averaging the clustering coefficient. If above a certain
number, then it is added to a list that has a chance of being thinned
out.

v0.71
- Having the same threshold for global threshold and local threshold in
clustering coefficients makes the thinning a little pro-active. I
separated these out to have two separate thresholds.