Queue up events before the UI is spawned

Queue up events before the UI is spawned

- Queue up any events fired to the UI before the UI exists
- At exit, check if UIs exist, and if not, flush the queue of LogRecords to
  the console directly.
- When establishing a connection from the UI to the server, flush the queue of
  events to the queue in the server connection, so the UI will receive them
  when it begins its event loop.

(Bitbake rev: 73488aeb317ed306f2ecf99cc9d3708526a5933c)

Signed-off-by: Chris Larson <chris_larson@mentor.com>
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>