ChatControlBase was split from ChatControl into its own module in commit
80221afc2c. With this split the import of the CommandContainer modules
was removed as well, likely because their members are not referenced
anywhere. However, importing these modules even when they are not used
directly is crucial because the contained CommandContainers are only
registered with the command system when their definitions are evaluated.
Import the modules with CommandContainers in chat_control_base.py to fix
the command system. Also add a comment stating more clearly why the
imports need to be kept around.
The goal of Gajim is to provide a full featured and easy to use Jabber/XMPP client. Gajim works nicely with GNOME, but does not require it to run. It is released under the GNU General Public License. If you find bugs or have ideas how Gajim can be better, please send tickets here.