Remove idle_event from examples/event_handling/idle_and_timeout.py #8296
Description
Running the example in examples/event_handling/idle_and_timeout.py produces the following deprecation warning:
$ pythonw examples/event_handling/idle_and_timeout.py
/Users/dstansby/matplotlib/lib/matplotlib/cbook/deprecation.py:106: MatplotlibDeprecationWarning: idle_event is only implemented for the wx backend, and will be removed in matplotlib 2.1. Use the animations module instead.
warnings.warn(message, mplDeprecation, stacklevel=1)
As the message says, idle_event should be replaced by something from the animations module.