Fix bug with empty or null host connection parameter in Oracle DSN construction

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.

DDC-217 - Add Result Cache feature

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

Named Parameters As Positional

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.

Fixed reference to non-existing class in docblock

Fix for ConversionException throw when the value is empty

OCI8Statement doesn't support first query parameter being null

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.