Add an PUT /topics/:id method to update topics

- adds the api method.
- Add the update method to the api client (not used).
- topic edit save function uses topic.$update instead of $save.
Merge remote-tracking branch 'upstream/master' into tweak-api

Conflicts:
	api/topicsData.js
Merge pull request #52 from dinoboff/tweak-api

Uses PUT /topics/:id to update a topic