Changed the display order of rich output in the live notebook to match that of nbconvert.  This makes more sense than the other way around due to the need for notebooks already shared on the web to remain consistant. Conversely local notebooks can simply be edited to match the new order.
Changed the display priority order back in the notebook and made mbconvert match the notebook
Merge pull request #7106 from damontallen/master

Issue  #7103: Changed the display order of rich output in the live notebook.
KernelClient: factor out generic async client from Qt client