Use gas_mod helper instead of local version

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Planner: use the traditional date widget

Much as I love the calendar, that meeds a little more tuning, so switch
back as we did for the maintab.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>