Adds a `using` statement to a `Query` overload

Adds a `using` statement wrapping the `DbDataReader` access missing in
`public IEnumerable<dynamic> Query(string sql, params object[] args)`
method overload.

This caused `database locked` errors when you executed a query followed
immediately by an `INSERT` to the database in methods using this `Query`'s
overload.

For example, using `First` method this way:

    var obj = table.First(...).id;
    table.Insert(...);

will yield a `database locked` error because the `rdr` in `Query` is
not being closed/disposed.

The other `Query`'s overload had it so I assume this one must had been
forgotten.