v0.2.0a0

• Support series 6 of ipykernel
• Switch to async interface, since this is how ipykernel works now

Breaking Changes

This library is now async. Synchronous operation is not supported.

- for i in with_ui_events(range(55), 10):
+ async for i in with_ui_events(range(55), 10):
       do_stuff(i)

  with ui_events() as ui_poll: 
-       ui_poll()
+       await ui_poll()

- run_ui_poll_loop(on_poll, 1/15)
+ await run_ui_poll_loop(on_poll, 1/15)