Squashed commit of the following:

commit d32d92038ee1312cde565b17c18a88c025ea8ec3
Author: Alexis Mineaud <alexis.mineaud@gmail.com>
Date:   Fri Feb 7 01:45:04 2014 +0100

    Fix sort by labels.

commit 17300ef1d2714d0c0d3ba50272b45096a33e3173
Author: Alexis Mineaud <alexis@gandi.net>
Date:   Thu Feb 6 18:30:00 2014 +0100

    Tring to communicate between the inbox with the filters...