Merged r11556 from trunk to 2.3-stable (#13391)
Czech translation changed by Karel Pičman.
Bulgarian translation ordered by Ivan Cenov (#13458)
Czech translation changed by Karel Pičman (#13450)
Fixing HTML in groups index view
Contributed by Gregor Schmidt.
Use #count instead of #size.
Log errors when bulk edit/copy fails (#13440).
Always instanciate a relation.
Moves Project#users to a regular method.
Moves Project#principals to a regular method.
Don't verify method.
