Make the DataAccessProviders class public

This class should be public so that it can be set if necessary (e.g.
from Web projects)
The Cascade attribute should override the default

The Cascade attribute should be checked first and override the default
behaviour if applied
Only mark the item as loaded if it's not null

Only mark the item as loaded if it's not being set to null
Support includes for joins

Support includes for joins (and other statement parts)
Make the generic database statements available

Make the generic database statements available to use
Don't clear all validation errors

Don't clear all validation errors when checking child items