with Cartodbfy being invoked by schema triggers. Some
issues with regclass interpretation in tests still remain.
Some issues with slightly different behavior to old version
remain. Some issues with error messages / notification messages
changing a little still remain.
Adds new _CDB_total_relation_size function that handles nonexistent
tables and does fallback to size=0.
That function could be used to cache total relation size or query another
table view with a cached total relation size.
Fixes#108
