Minimal double reader.
Upgrade JSONField.
Tags i18n.
Allow books with internationalized metadata.
Merge branch 'master' into rwd

Conflicts:
	apps/catalogue/templates/catalogue/book_short.html
	apps/funding/static/funding/funding.css
	apps/wolnelektury_core/templates/main_page.html
Merge branch 'minimal-double-reader' into rwd
minor style fix
More work on new HTML reader.