Clean up date and timezone handling. We used to pass changelog dates around as a "unixtime timezone" string containing a pair of encoded ints. Now, they get passed around as a (unixtime, timezone) tuple of numbers, which makes much more sense.

#!/bin/sh

hg init

echo "Is there an error message when trying to diff non-existing files?"
hg diff not found

echo "Is there an error message when trying to add non-existing files?"
hg add not found