v0.3.0

• refactor models to use URI, URI Prefix, and Key
• refactor tests, remove factory_boy
• add test fixtures
• add XML export
• add XML import
• fix i18n switcher
• fix dates in project_answers_tree
• fix yes/no widget

After running the migrations, use

./manage.py set-uri-prefix 'https://example.com/terms'

(with example.com replaced by your domain) to initialize the URI.