Test /events and /labels, especially auth

[osteele]

b7f354e Add more event tests

Starts #103.

Creates stubs for #75 (marked in test_events.py by a TODO).

Issues #218, #217, #216 and ,#215 should add to these tests.

937445b Minor improvements to test_events.py

• Rename the test case.
• it's no longer necessary to set app.debug

2adaea2 Add test cases for /labels

Also in label_resources.py:

• Change a logger.warning to logging.debug, since it's not a server issue if this happens (and this was chattering at the test suite)
• Letter logger.{debug,info} do the string formatting instead of passing it formatted strings — for style and efficiency

[osteele]

@songbird175 if you've got work on this branch ready to go you can push and it will go in this PR. Otherwise rebase from or merge dev once this is merged. (I'm trying to keep mergeable changes from hanging out on branches for too long.)