- [bug] implement 'tablename' parameter on

- [bug] implement 'tablename' parameter on
  drop_index() as this is needed by some
  backends.

- [feature] Added execution_options parameter
  to op.execute(), will call execution_options()
  on the Connection before executing.

  The immediate use case here is to allow
  access to the new no_parameters option
  in SQLAlchemy 0.7.6, which allows
  some DBAPIs (psycopg2, MySQLdb) to allow
  percent signs straight through without
  escaping, thus providing cross-compatible
  operation with DBAPI execution and
  static script generation.