Use more reliable timestamps for some kinds of events on Haiku

Use more reliable timestamps for some kinds of events on Haiku

* src/haiku_support.cc (DispatchMessage):
(MouseMoved):
(MouseDown):
(MouseUp): Set `time' field of event structures to input server
time.
* src/haiku_support.h (struct haiku_key_event):
(struct haiku_mouse_motion_event):
(struct haiku_button_event): New field `time'.
* src/haikuterm.c (haiku_read_socket): Use input server time
if provided.