Exclude overviews from user data size

Fixes #261

Some internal functions from the Overviews module
have been moved to a separate file because they're now
used from Quaota function.

test/extension/run_at_cartodb_schema.sql

@@ -4,4 +4,4 @@ SET SCHEMA 'cartodb';
 \i scripts-available/CDB_ColumnNames.sql
 \i scripts-available/CDB_ColumnType.sql
 \i scripts-available/CDB_AnalysisCatalog.sql
-SET SCHEMA 'public';
+SET SCHEMA 'public';