libc: add clock_getres()/clock_gettime() system calls.

In order to make it more clear that ticks should be used for timers
and realtime should be used for timestamps / displaying the date/time,
getuptime() was renamed to getticks() and getuptime2() was renamed to
getuptime().

Servers, drivers, libraries, tests, etc that use getuptime()/getuptime2()
have been updated. In instances where a realtime was calculated, the
calculation was changed to use realtime.

System calls clock_getres() and clock_gettime() were added to PM/libc.

drivers/orinoco/orinoco.c

@@ -346,7 +346,7 @@ static void or_reset() {
 	t_or *orp;
 	int i, r;
 
-	if (OK != (r = getuptime(&now)))
+	if (OK != (r = getticks(&now)))
 		panic("orinoco: getuptime() failed: %d", r);
 
 	if(now - last_reset < system_hz * 10) {