doc folder in tarball @ pypi absent of .inc files; networkx-1.9.1

The doc build (in release 1.9.1 is huge, however there are many warnings reporting absence if files of suffix .inc in folder doc/source/developer/gitwash. 

InputError: [Errno 2] No such file or directory: 'source/developer/gitwash/links.inc'.

Sure enough in MANIFEST.in

recursive-include doc *.py *.rst Makefile *.html *.png *.txt *.css

Please add *.inc to MANIFEST.in