Emit the resume signal before we update

Emit the resume signal before we update

[Problem]  We'd signal the application AFTER we'd already done a first update
           upon resume so the first frame shown would just show the last frame
           before we were paused.
[Solution] Emit the signal first on resume so the application can queue any
           messages. Then we should process the messages (but only once as
           Core::Resume also does it). Finally, we should kick off the thread
           controller, so the first update that we do is what was required by
           the application.

Change-Id: I6dda0b70f29b47da91f5dc430447b54f7526067d