azoff/verbatim — pull request #57 by azoff (2014-04-16 12:13:17+00:00)
Title: User source property + listener count

Parent #56
Closes #55
Relates #57

- Adds `source` property to `VBUser`
- Adds `listenerCountWithSuccess:andFailure:` to `VBUser`
- Adds `VBUserEventSourceChanged` event, triggered on source change
- Modifies `VBInputSourceManager` to observe `VBUserEventSourceChanged` and change input
- Moves `sourceUser` to private property of `VBInputSourceManager`
- Adds test method for user source count
- Nils source on user check out