Hide the timeout/establish view when a timed out window gets an incoming call
Don't send hangup when we're in the timeout state - we've already sent one.
Move testing for the call state when hanging up into the call model.
Remove last call.hangup() caller, and mark it clearly as an internal-only API.
Change back to just one hangup function and add a few comments for future clarity/refactorings.
Merge branch 'master' into fix_timeout_view
Merge pull request #218 from Standard8/fix_timeout_view

Ensure we hide the establish/timeout view at the right times, and don't send hangup in timeout state