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.
Fixes test failure when running all functional tests.
Merged r6170 from trunk.
Fixes a functional test case.
Adds css for syntax highlight on welcome page (#8512).
Adds a 'New version' link on the roadmap.