Implement an ORM based on composite casters
Preen docs on orm
Fix one_or_zero to dereference always for 1 col
Update our own usage of one_or_zero
Take unicode markers out of docstrings

Python 3 doesn't have them, and we want to be Python 3.
Add another error check to register_model
Tests need to be brought up to date
Expose cursor_factory to all and one_or_zero
Support cursor_factory=dict and =tuple
Bump version to 2.0.0-dev