* agent: return a non-zero exit code on error
* agent/template: always return on template server error, add case for error_on_missing_key
* agent: fix tests by updating Run params to use an errCh
* agent/template: add permission denied test case, clean up test var
* agent: use unbuffered errCh, emit fatal errors directly to the UI output
* agent: use oklog's run.Group to schedule subsystem runners (#9761)
* agent: use oklog's run.Group to schedule subsystem runners
* agent: clean up unused DoneCh, clean up agent's main Run func
* agent/template: use ts.stopped.CAS to atomically swap value
* fix tests
* fix tests
* agent/template: add timeout on TestRunServer
* agent: output error via logs and return a generic error on non-zero exit
* fix TestAgent_ExitAfterAuth
* agent/template: do not restart ct runner on new incoming token if exit_after_auth is set to true
* agent: drain ah.OutputCh after sink exits to avoid blocking on the channel
* use context.WithTimeout, expand comments around ordering of defer cancel()
