compiler: allow objects and records to have members which point to themself. only don't permit this to regular fields.
  - remove testcurobject hack and perform a check only for regular fields
  - move is_holded_by to interface and rename it to is_owned_by
  - don't check static symbols in _needs_init_final because they always point to symbols registered on unit level
  - don't check object type in id_type, read_named_type when we are looking for type of structure member - the only check will be performed for record/object fields now
  + tests

git-svn-id: trunk@16646 -