Announce 3.17.91 release

The To Do development team proudly announces the availability
of GNOME To Do 3.17.91!

News for this version:

        * Add selection mode, which allows renaming and removing lists
        * Add a "Clear completed tasks..." item in gear menu
        * Update build system (Emmanuele Bassi)
        * Lots of bugfixes and cleanups

        * Catalan (Jordi Mas)
        * Esperanto (Kristjan Schmidt)
        * Galician (Fran Dieguez)
        * Greek (Dimitris Spingos)
        * Hebrew (Yosef Or Boczko)
        * Hungarian (Balázs Meskó)
        * Lithuanian (Aurimas Černius)
        * Norwegian bokmal (Kjartan Maraas)
        * Portuguese (Pedro Albuquerque)
        * Polish (Pedro Albuquerque)
        * Punjabi (A S Alam)
        * Spanish (Daniel Mustieles)
        * Slovak (Dušan Kazik)
        * Turkish (Muhammet Kara)