…e clarify

* temporary need for compatibily with other patched.

… for specified [ppm]

+     rtcTime() - now rTimer value not equals to simulation time, but takes to acount clockDrift
+     setClockDrift - provide random clockDrift from specified range
+     provided UI - there shows time and drifts, and allow setup drift value.

…ionTime vs

        rTime values decimated by clock drift.

        if drift go rtc faster, then appears jumps in rtc sequence, to realise speedup rtc sv simulation time.
        if mote waits value exact in jumped gap, then it's firmware may loose awake.
        To prevent it, do correct simRtimerNextExpirationTime, so that go after jumped gap, if need.