* idSysSignal::Wait should now handle timeouts > 1s better (or at all)
* Use clock_gettime for Sys_Milliseconds()
* Use CLOCK_MONOTONIC_RAW (and CLOCK_MONOTONIC as fallback if
that's not available) for Sys_Milliseconds() and Sys_Microseconds()
CLOCK_MONOTONIC can behave strange when NTP is used
* Small fixes in Sys_Microseconds(): use 64bit int to store time
(like return type...), divide by 1000 (not 1000000) for nsec=>musec
