previous changes in bindparam function

Updated OCI8Connection parameter name in order to separate oracle pooling handling with oci8 persistent connections

Adding PDO::FETCH_COLUMN support to OCI8 fetchAll method using the fetch structure OCI_FETCHSTATEMENT_BY_COLUMN.

This is necessary because pdo_sqlsrv still has some little bugs that
prevent it from being used in all use-cases. Additionally only sqlsrv
can make use of the Azure federations features.