[FIX][BUG] Chronology DateAndTime class>>now returns incorrect time ( use v1 )

[avi at beta4.com]

I think we should use the first version I posted for now, since there's
some debate about monotonicity regarding millisecond resolution.  I'm
also not totally sure my millisecond calibration is reliable - HMM
thought there might be possible race conditions.  Better to be accurate
but less precise for now, and continue to hash out the precision stuff.