fix xpath for group_name

- use @owner_id instead of owner_id (in casedb)
- use current()/@owner_id when embedded in another context
- use explicit comparison count(...) != 0, since xpath doesn't do
  falsiness
add candy coating to UI for Owner Name in case list
Merge branch 'owner_name' into multimedia-case-properties+owner_name

Conflicts:
	corehq/apps/app_manager/static/app_manager/js/detail-screen-config.js