Update nose configuration to include coverage.
Do not include coverage from networkx.external
Adjust regex for test discovery.
Now, networkx.testing is not considered a test.
Copy nose configuration to installation directory before testing.
Better comments about TravisCI installations.
Clean up comments a bit more.
Attempt to submit coverage only for 2.7
Merge pull request #993 from chebee7i/coverage

Make nose and coveralls coverage levels match.