BUG: fix test_read_LEDA on windows.
Use io.BytesIO() instead of temporary file
Don't add edges from "padding" in sparse6 format
PEP-8 cleanup; attribution
Remove spurious print
fix error when pickling frozen graphs
Fix error in testing/utils: assert_graphs_equal was not correct for multi graphs
added tests for checking if pickling is working correctly (with different types of graphs, frozen and unfrozen)
Merge pull request #963 from Tscheik/master

Fix error when pickling frozen graphs.
Merge branch 'master' of github.com:networkx/networkx
Fixes networkx/networkx#966 typo in simple_cycles.
Merge pull request #967 from brianthelion/master

Fixes #966 typo in simple_cycles.
Merge pull request #956 from hagberg/sparse6-nodes

Sparse6 format padding fix

Fixes #955
Merge pull request #968 from hagberg/cournape-fix_windows_filemode

Windows compatibility for read LEDA test

Fixes #946
Better method for moving to install directory for travisCI.

This method is better since it doesn't rely on importing networkx.
If networkx fails to import, possibly due to dependency or syntax
errors, then we wouldn't change directories. And then no tests
would be run.
Make coverage report ImportErrors.

This makes travisCI report failures when they are caused by dependency
issues or syntax errors or ...