Add all the events

[chc4]

XServer::get_event should handle most(if not all) of the event types.
It should also wrap the important/relevant members of the event into an enum it returns. Also, fix your naming - match on a ButtonPress, cast to XButtonPressedEvent, and return a ButtonPressed? That's terrible.

[chc4]

With Enum variants being namespaced now, the ServerEvent variants are named the same as the XEvent ones (just with extra information for a match to act on)

[chc4]

This is pretty much just a duplicate of #3 now.