Handle tornado 6.X versions. (WebThingsIO#47)

Fixes WebThingsIO#46

Add support for Python 2.7 and 3.4. (WebThingsIO#41)

Fixes WebThingsIO#40

Update CHANGELOG.

Update CHANGELOG.

Validate property values with JSON schema validator. (WebThingsIO#31)

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)