Ensure SelectLimit $nrows and`$offset parameters are integers
Ensure SelectLimit $nrows and`$offset parameters are integers

The same is done (at least for `$nrows`) in the `SelectLimit` method of `Adodb/adodb.inc.php`.

This lowers the risk of SQL injection.

Fixes #311

(cherry picked from commit 7d43989dc95fd00fcf3ba73e08fdaf56ffa4f3e5)

ipso/ADOdb,ipso/ADOdb