This enables a more natural way of interacting with result sets,
and re-introduces in Doctrine DBAL a feature that has been available
in PDO from the begining.

DDC-1266 - Fixed bug where one sequence is dropped multiple times and extended that logic to tables and constraints

DDC-217 - Refactor result caching to use a value object for all the important information which simplifies the code considerably and makes caching more powerful.

DDC-217 - Refactor result cache again to be much simpler, previous approach was too complicated and something like this needs longer testing. Now only caching the full result.

Fix bug where empty or null host connection parameter will still construct an Oracle DSN instead of using dbname.

DDC-1337 - MySQL commits transaction on DROP TABLE, need DROP TEMPORARY TABLE. Added tests, looks like oracle commits transactions on CREATE TEMPORARY TABLE. I dont know how to fix it.

This reverts commit 869cb960.

Patch for OCI8Statement to support param[0] being null. Switched isset to array_key_exists. Added test that demonstrates the bug and confirms the fix.