Adding several tests to jetpack network tests

This commit adds several unit tests to the jetpack-network
tests and updates two existing tests (one update trivially).
get_url() is tested in more depth, as its return values are
very specific and can be tested very specifically.
Minor commit to switch back to tabs after switching to spaces
Merge pull request #953 from enkrates/add-and-update-jetpack-network-tests

Adding several tests to jetpack network tests