- refactor migrate.changeset;

- visitors are refactored to be more unified
- constraint module is refactored, CheckConstraint is added
- documentation is partialy updated, dialect support table is added (unfinished)
- test_constraint was updated
NOTE: oracle and mysql were not tested, *may be broken*

migrate/changeset/__init__.py

@@ -4,5 +4,11 @@
 
    .. [#] SQL Data Definition Language
 """
+import sqlalchemy
+
 from migrate.changeset.schema import *
 from migrate.changeset.constraint import *
+
+sqlalchemy.schema.Table.__bases__ += (ChangesetTable, )
+sqlalchemy.schema.Column.__bases__ += (ChangesetColumn, )
+sqlalchemy.schema.Index.__bases__ += (ChangesetIndex, )