Time display inconsistent when client-side time is a few minutes behind

There are currently some odd behaviours if the client-side system time is behind.

• To reproduce, modify system time on client
• create a new issue ticket
• Issue's activity tab will show the date/timestamp instead of the human readable "Few moments ago"
• In GreenHopper, columns will show "-1 days in column", instead of "0 days"

Although the above is to manually reproduce the problem, it can occur with NTP-adjusted systems where the time is a bit off.

The time data stored into the database is not affected, this is purely a display issue on the client side.