API: Internal cleanup

* Separate client-visible and internal release notes, because there are
  a lot of both and will be more coming up
* Correct errors in release notes
* Add detail on token changes to release notes
* List deprecated API classes and methods in release notes
* Add missing @deprecated on ApiFormat* classes

Change-Id: I577f3c8b9182f1625470c8bc52d3bdfe5d623d81