Update messaging system:

* Now messages come in time-sliced chunks
* Batched messages are pretty-printed to output pane
* Colours changed
* Thread name printed if available
* Job id printed
* Virtual time of message printed
* Messages threads are killed when user stops
  (inhibits delayed messages from arriving after stop)
* Non-timed messages are now sent via /info OSC messages and are printed
  immediately with no job/time/thread info.