java.util.Timer. We might as well use the standard stuff, and why not:
it's got a snazzy priority heap for scheduling.
However, we still like the flexibility of IntervalManager's static methods
and the Interval interface (Timer's helper, TimerTask, is a class. Boo.).
Note: I ripped out so many guts that we no longer have the ability to
use a pool of helper threads for expiring Intervals. We never used it
anyway. If we desire it in the future, it'd be easy enough to put back in.
git-svn-id: https://samskivert.googlecode.com/svn/trunk@757 6335cc39-0255-0410-8fd6-9bcaacd3b74c