- Allow access to poperties of the "application" OSA class directly from

the toplevel package. This already worked for elements, but now for
properties too. Fixes #753925.
- Even better, the toplevel class (such as Finder.Finder) now inherits
the element and property dictionaries of its application class and has
the necessary glue to allow you to say
  f = Finder.Finder()
  f.get(f.name)