Fix typo.

Fixes WebThingsIO#29

Bump version.

Add better property value validation. (WebThingsIO#26)

Implement read-only properties. (WebThingsIO#25)

Implement Action, Event, and Properties resources. (WebThingsIO#23)

Bump version to 0.5.4.

Validate action input. (WebThingsIO#7)

Fix period update of level in example. (WebThingsIO#6)

Tornado doesn't play nicely with threading, so we have to use
IOLoop to update the level.

Fix JSON decode errors.

Drop Python 2.7 support.