Merge pull request #4 from tituomin/master

Set charset to utf-8 in the renderers.
Working YSA importer
UTF fix.
Merge remote-tracking branch 'tituomin/master'
Add classes for serializing MPTT and translated models
Enable django-extenions for manage.py extensions
Bug fix
Add allärs datasource.
Add alternative labels to categories.
Unfinished kulke category matcher.
Bugfix: remember to return saved category.

Necessary for parent / child relationships.
Bugfix: method call signature.
Textual category matching. Categories added for kulke events.
Merge remote-tracking branch 'tituomin/ysa'

Conflicts:
	requirements.txt
Trim currently unusued fields from models.py
Trim down currently unused code even further
Rename Event.category -> categories as it's a ManyToMany relationship
Add verbosity option handling to importing
Add missing migration
Implement better handling of dates when filtering for events