Fixes #154 The "other languages" in general settings is preset on the default language

Disable the default language in the "other languages" list
Merge branch 'back-office-other-languages' of git://github.com/Nesk/mayocat-shop into Nesk-back-office-other-languages
Also disable already selected other languages
Merge branch 'Nesk-back-office-other-languages'