1)clean the couch_api_server
2)extend the couch_api_db
- get_db_info/2
- create_db/2
- delete_db/2
- get_db_changes/2
- get_db_changes/3
- compact_db/2
- compact_view/3
- cleanup_view/2
- ensure_full_commit/2
- bulk_docs/4