Add *.inc to doc build.
Merge pull request #1263 from chebee7i/issue1263

doc folder in tarball @ pypi absent of .inc files; networkx-1.9.1
enhance docs for centrality measures, close #1257 close #1250 close #1247
Merge branch 'master' of https://github.com/Michael-E-Rose/networkx into issue1266
Some minor touchups, file encodings, etc.
Build and use the latest IronPython code from IronLanguages/main