post_update updates too many columns

[Mike Bayer]

when post_update does the second UPDATE statement, it updates all columns that were already inserted. it should be modified to update only those columns that were affected by the ClauseSynchronizer used by the post_updated property. mapper should get a separate function for post_update since its somewhat different from save_obj/delete_obj.

the unittests in cycles.py use tables that have only the foreign keys and should have some extra "data" columns put in there to test this.

[Mike Bayer]

this is fixed not just for too many columns but also for too many rows in changeset:1872

[Mike Bayer]

Removing milestone: 0.3.0 (automated comment)