fix typos
Merge pull request #23 from yoloseem/master

Fixed two typos.
added "system=True" to Column, so that we generally don't have to bother
with CreateColumn rules
forgot to add system to the copy() method

Conflicts:
	lib/sqlalchemy/schema.py
- The ``version_id_generator`` parameter of ``Mapper`` can now be specified
to rely upon server generated version identifiers, using triggers
or other database-provided versioning features, by passing the value
``False``.  The ORM will use RETURNING when available to immediately
load the new version identifier, else it will emit a second SELECT.
[ticket:2793]
- The ``eager_defaults`` flag of :class:`.Mapper` will now allow the
newly generated default values to be fetched using an inline
RETURNING clause, rather than a second SELECT statement, for backends
that support RETURNING.
- Added a new variant to :meth:`.ValuesBase.returning` called
:meth:`.ValuesBase.return_defaults`; this allows arbitrary columns
to be added to the RETURNING clause of the statement without interfering
with the compilers usual "implicit returning" feature, which is used to
efficiently fetch newly generated primary key values.  For supporting
backends, a dictionary of all fetched values is present at
:attr:`.ResultProxy.returned_defaults`.
- add a glossary entry for RETURNING
- add documentation for version id generation, [ticket:867]
- restore constructor docs blown away in the merge
migration for version id feature, eager_defaults
- fix server-side non-returning example
- mention eager_defaults
- ensure rowcount is returned for an UPDATE with no implicit returning
- modernize test for that
- use py3k compatible next() in test_returning/test_versioning