Cannot handle event loop set up and tear down in 1.0

[schlamar]

Before 1.0 you could use the "event_loop" fixture for custom set up and tear down instructions on the event loop.

With removal of the fixture in 1.0.0 there seems to be no way to access the event_loop before it is running and after it has stopped.

Example use cases:

• define exception handler to fail test if exception occurs
• clean up pending tasks after test has run