Modified Python example to match ari-py

Modified the Python example to work with the new approach used in ari-py
for passing arbitrary arguments to callbacks.

Fixed a bug where it was possible for timers to overlap.
Merge pull request #1 from asterisk/arbitraryparams

Modified Python IVR example to match new arbitrary parameters syntax
example.js: Fix syntax errors; call ChannelLeftBridge callback on channels

In addition to fixing some egregious and obvious syntax issues, this patch
also makes it so that the ChannelLeftBridge handler is called on a channel
leaving the bridge, as opposed to on the bridge itself. This allows for
safe destruction of the bridge when the channel count reaches 0. Previously,
the callback was called for each channel in the bridge when a channel left,
which would cause the application to attempt a bridge.destroy() more than
once.
example.js: Use .once instead of .on for events that should only occur once

This includes the PlaybackFinished event for the periodic announcement
messages, as well as the ChannelLeftBridge event (as we only expect them
to be leaving the bridge one time).
Merge pull request #2 from matt-jordan/infinite-wait

bridge-infinite-wait: Update examples to have a periodic playback
Merge branch 'master' into dial
Update bridge-dial/example.py

Add some additional error handling, and dispose of bridges
when either channel leaves the application.