Comply with semantics described in TEP, use HilTimerMilli as base for LocalTime in...

TestFtsp works, however FTSP relies on the assumption that
message_t.data = call Send.getPayload (just like BaseStation)
but this is not true for RedMac/SpeckMacD on an eyesIFX node.

After suitable modification of TimeSyncP (replace
TimeSyncMsg* msg = (TimeSyncMsg*)(processedMsg->data);
with
TimeSyncMsg* msg = (TimeSyncMsg*)(call Send.getPayload(processedMsg, sizeof(TimeSyncMsg)));
it works.