0.3 cleanup

[Mike Bayer]

list:

• move/remove get_id_key/get_row_key from Session to mapper
• remove mapper.select()/query()/etc. methods
• move mapper._instances(), mapper._instance() to Query.
• optional: restore ExtensionOption since Query will be doing _instances and can apply a local MapperExtension during querying
• optional: mapper.save_obj(), delete_obj(), moves to new module "persister" class EntityPersister
• move topological.py to base package since its used by table sort
• fix order of classes in unitofwork.py to be in order of dependency
• make method names in unitofwork.py consistent with regards to public/private naming scheme
• remove _mark_modified() stuff from UOWTransaction

[Mike Bayer]

most of this is in changeset:2009, changeset:2010

[Mike Bayer]

the last of it is in changeset:2034. we're not moving save_obj, delete_obj, _instance out of mapper right now.

[Mike Bayer]

Removing milestone: 0.3.0 (automated comment)