Add necessary SQL scripts for migrating from 0.8.0 to 0.8.1

0.8.1 should have the same SQL schema as 0.9.0, so that user would upgrade his schema from 0.8.0 to 0.8.1 and then upgrade code to 0.9.0 . We'll stop using SQL scripts and use South instead. One more thing that needs to be done is drop Endpoint.contact_addr field that is not used.