Patches sent from Vladimir Sekissov <svg@surnet.ru> applied manually

Patch changes summary:

* Search presentation now works as expected. Search criteria and queries
are dispatched to appropriate backend.
Added :presentation-search (could be subclass of mewa:mewa-presentation-search)
view to model.

* Fixed creation of meta-model class with distinct name

* Added :fill-gaps-only keyword to meta-model:sync-instance
With :fill-gaps-only true instance is not saved to database,
only default values and join slots are setted. Previous
behaviour failed on tables with not nullable fields without
defaults.

* Prepend generated slot accessor name with view name if it conflicts with existing functions.

* Various small fixes.

Best Regards,
Vladimir Sekissov

darcs-hash:20050629221441-5417e-0a1370d295df6cb6c9ce2f43c0b9c676d3ce7942.gz