removing the need for flags in chronos.c
Fixing micro/nano second bug

Initially microseconds were used (and the range capped correctly),
 then the range cap was used on nanoseconds (which are 1000 times
 larger), which caused key insertion that wasn't in sorted order.

I.e. the most significant parts of the nanosecond timing were cut
 off (incorrectly) by the microsecond cap.