Makes relations resource shallow (#7366).
Makes versions resource shallow (#7403).
Adds breadcrumb on all wiki page views.
Removed leading dash in ruby code.
Adds REST API for versions (#7403).
Adds support for GET on /issues/:issue_id/relations (#7366).
Document why relation is reversed after validation.
Set a default value for relation type.
Adds REST API for issue relations (#7366).
Merged r6163, r6171, r6172, r6174 from trunk.