Report event time stamps

[fhunleth]

The Linux input event system reports events with timestamps attached. It would be nice to pass those timestamps through to Elixir. Here are some reasons:

1. If the timing between events is critical (like for a double click), then the Linux timestamp is the best one to use.
2. Frameworks like scenic forward events using message passing. Processes that collect events from multiple places (like the text entry collector for an on screen keyboard where each key is a process) run the risk that events are misordered. This is probably low since computers are fast, but event timestamps would disambiguate the order.
3. The timestamp is available, so why not pass it up?