Add option to prevent throwing exception when computer clock is adjusted backwards

[pbolduc]

The current code will throw InvalidOperationException if the time on the computer has been adjusted backward. This will occur if the clock has skewed forward and is adjusted backwards using NTP.

Suggestion is to allow a configurable behavior that will pause id generation until the adjusted clock catches up. This behavior should provide for a max skew wait time and should have reasonable defaults.

This is not related to daylight savings.