timer events

[Eric Dean Tribble <tribble>]

I just realized yesterday that time events (delays and such) should
work just like mouse motion events.  Events virtually exist at
arbitrarily small granularities, but the system only generates them
when a controller actually cares (very rarely).  This is cleaner than
my original design (or lack thereof). 

Controllers will use TimeEvents to bring up hint windows when the user
holds down the mouse, automatically scroll when selection goes out of
a window, etc.

dean