callOnEachEvent does not forward event types correctly

[palaga]

Can be easily reproduced by running queue_helper.js from the examples directory. Update the zuliprc file path, so it points to a valid rc, and run the example script. Now type a message in some chat and monitor the output of the example script. Typing events will pop up, while only message events are expected.

After inspecting the source, it looks like the parameter is passed as eventType instead of event_type.

Renaming all instances of eventType with event_type in events_wrapper.js seems to fix it, except that I keep seeing heartbeat events. Just renaming might not be an elegant solution, as it goes against naming conventions, but it should be easy to fix nonetheless.