Update tag documentation

* Remove email/latitude/longitude
* Add actor/owner (although I'm not sure exactly what these mean)
* Add delete tag API
* Mark create/delete API as "internal"
* Create API returns TRUE, not the created tag
* Removed update API examples

I'm not sure exactly what distinguishes actor and owner. @jmathai, can you comment?

I removed the update examples, since this endpoint doesn't actually appearto have a purpose at present.