Right now, [hid] basically outputs events in response to the OS.  It polls the
event queue at a given frequency and processes everything in the queue on each
cycle.  This means that the data stream is a bit erratic.

The first part of the question is whether [hid] should output everything it
finds in the event queue, or just the most recent event.

- buttons output every event, since its state change (on/off) triggers something.

- For absolute axes, it probably should just output the most recent event per
  poll, since absolute axes are position, and its not really necessary to know
  how many events there were between [hid] polls, just the position where it
  ended up.