Changes

* Have several threads execute for loops that the timer interrupt print out a series of statements. Check that statements for different threads are all printed contiguously and in ordering consistent with their respective wake times. * Have a main thread print out system times with a set frequencydebug statement, and have timed threads print the times they go to sleep and when they have exceeded their wait timeswoken up. Verify that they execute wake up relatively close to their expected exit time. * Make sure threads called with illegal times return immediately. Test threads that go to sleep chronologically in order (1, 500, 1050) as well as threads that go to sleep with the same times ( 50, 50) and threads that go to sleep in reverse order (500, 250). Verify they all wake up when they are supposed to.