Postgres tables not cleaning

A few problems came up for us:

1. When `database-cleaner` lists out the tables to be deleted, the tables are not ordered by foreign key constraints. So we have `child` with a foreign key to `parent`, but `DELETE FROM "parent"` is attempted to be run before `DELETE FROM "child"`, causing the table to not be deleted because there are still rows in `child` referencing `parent`

2. When the above command didn't work, `database-cleaner` silently failed. I believe `database-cleaner` should check that the table was indeed cleared, and error otherwise.

Truncation seems to work for us. Is there a reason why truncation is not the default?