feeling good about release cowdb0.12

The cowdb0.12 release has had a major cleanup. The code has now been refactored to the point where calling free on an object gracefully removes it from any arbitrary object graph. A container interface has been added. And bugs have been found/fixed in handle and the various container iterators. A new method, all, has also been introduced on the Display class which lists all the objects in the well known table. Overall I'd say that cowdb is now a lot more programmer friendly.

The next step now will be to do a similar cleanup on COODBMS.