Used customized AppConfig classes in openslides.core, openslides.account, openslides.projector, openslides.agenda, openslides.motion, openslides.assignment, openslides.users, openslides.mediafile, openslides.config. Refactored loading of signals, template signals and slides.
* New user model (used Django's AbstractBaseUser) * Renamed the app to users * removed person api See #861 Fixed #576 #478