remove some duplication
Remove pointless redirection
Move get_parent function to dbfactory
Move get_parent_guid_uncached functions to dbfactory, where the corresponding cache
is located.

DBA classes can still define those methods (and they will be preferred over the
dbfactory ones), but they are no longer available by default (and there is no good
reason for calling them from component code anyways)
Fix mgd2 warnings
Change get_parent logic to reduce duplicate caching of dba objects.
this also fixes a problem where get_parent could return the wrong
class when multiple mdgschema classes use the same db table
Add workaround for strange deletion problem
Remove local get_parent workarounds that are no longer needed
Merge branch 'master' of github.com:flack/openpsa
Make classnames match path
Add basic tests for some parent-related functionality
Remove unused function
Add some more cases to test
Also store parent class in cache, since this will allow us to
avoid a few unecessary get_object_by_guid calls and help reduce cache
duplication
Use parent class information in acl backend for better performance on
cache misses