Fixes multiple issues
- Unicode errors when path contained non-ascii characters
- 403 errors when the current working directory was not a parent
directory of the static files
- "API abuse" super() implementation of the get() method was passed a
filesystem path instead of the url-path it was expecting
- The above could also lead to 403 errors on case-insensitive file
systems due to the way the base-class resolved and validated paths
with respect to self.root
* Update projector when polls are updated.
* Update projector when assignment candidates are updated
* Update projector when motion submitter are updated
* Fixed the assignment publish poll view
* Added projector.api.register_slide_model
* Set a static projector title
* absolute_urls for the activate links
* update the projector when a slide changes (in save())
* insert the absolute_url template filter
* Preview to slides
* renamed is_active to is_active_slide
* The SlideMixin has to come before the PersonMixin
* Update list of speakers
* Render Countdown via JS
* Reconnect projector after connection lost
* Overlays can allways be active and do not appear in the widget
* Rewrote the clock as overlay