This patch undoes the change in the order of timer parameters for:
net.accept() net.recv() tmr.delay() tmr.setclock() tmr.set_match_int()
tmr.gettimediff() and also changes the new tmr.getdiffnow() to have the
same parameter ordering as the others.
The default timer ID (the systimer), which previously was obtained with an
optional last parameter, is now obtained by supplying nil as the timer ID.