Split front page of website to networkx-website.  Add gh-pages function to push docs to networkx-doc github site.
Switch docs from networkx/networkx-doc to networkx/documentation.

Add Makefile target.
Missing tab in Makefile
Match navbar in docs to website
Merge pull request #806 from hagberg/doc-split

Split front page of website to networkx-website.  Add gh-pages function ...