fix tests to know that date math affects local time, not utc add more tests because of this
fix tests to know that date math affects local time, not utc
add more tests because of this

1nickt/DateTime.pm,1nickt/DateTime.pm,chansen/DateTime.pm,1nickt/DateTime.pm,chansen/DateTime.pm,chansen/DateTime.pm,autarch/DateTime.pm,autarch/DateTime.pm