Add ensureStatementsReturned method
* Handle the case where zero statements are returned but a more link is present
Add call to _ensureStatementsReturned in moreStatements
* Make sure that _ensureStatementsReturned isn't called a second time from moreStatements calls issued from within _ensureStatementsReturned
* Make sure that _ensureStatementsReturned isn't called a second time from queryStatement calls issued from within _ensureStatementsReturned