Merge pull request #8 from stevenweaver/master

Adding betweenness centrality
Merge pull request #9 from stevenweaver/master

removing default betweenness calculation
Merge pull request #10 from stevenweaver/master

adding betweenness calculations for JSON output, albeit correctly this t...
Merge pull request #11 from stevenweaver/master

changing python path
commenting out rpath
Merge pull request #12 from stevenweaver/master

fixes dot file option
resolving veg conflict