By default mysql connection doesn't use DQL record limit (it doesn't support limit in subqueries yet)
* Added some test cases for the importing part. The new tests will fail for now because of the lacking implementation. Refs #11
Fixed Doctrine_Record::exists() and removed final attribute since its *not* a method that is used by Doctrine internally
Added exists() to check for existence of data, getColumnCount() as alias to count() and renamed has() to hasRelation() for clarity