Test events API

The Socket IO / events controller currently has poor test coverage:

```
jaraco/abode/event_controller.py 169 28 83% 61, 65, 69-76, 80-87, 127, 175, 180, 184, 188-200, 204-208
jaraco/abode/socketio.py 230 135 41% 89, 92, 115-118, 122-125, 130, 140-147, 151-159, 162-185, 188-211, 214-218, 221-227, 230-247, 250-264, 267, 270-282, 285-289, 292-293, 296-308, 311-313, 316-320, 323-325, 328-339, 342-349
```

As a result, bugs such as those in #14 were allowed to creep into the project.

Today, I did a search and found [mocket](https://github.com/mindflayer/python-mocket) that looks pretty mature and may enable testing some of the websocket behaviors.

Start by reading event_controller.py and socketio.py, focusing on the uncovered lines listed in the issue and evaluating whether mocket can exercise the websocket behaviors. Done means the events API has meaningful tests for those paths and includes coverage for regressions like #14.

Written by the indexing model from the issue text.