v0.1.7

• Added Lazybones.Backbone so the version of Backbone used with Lazybones is easily accessed.
• Added .isConnected() to test if a Lazybones instance is actively listening to the PouchDB changes feed.
• Lazybones instances proxy the "error" and "destroyed" events from the underlying PouchDB instance.
• .destroy() can now only be called once. Further calls do nothing and return a promise that resolves instantly.