This library lets you create a one-shot timer, poll it using STM, and update it
to ring at a different time than initially specified.
It uses GHC event manager timeouts when available (GHC 7.2+, '-threaded',
non-Windows OS), yielding performance similar to 'threadDelay' and
'registerDelay'. Otherwise, it falls back to forked threads and 'threadDelay'.
[0.1.1] Add tryWaitDelayIO, improve performance for certain cases of 'newDelay'
and 'updateDelay', and improve example.