1. `FetchMode::STANDARD_OBJECT` and `FetchMode::CUSTOM_OBJECT` are no longer supported.
2. `FetchMode::COLUMN` with a non-zero index is no longer supported.
3. Incompatible change in the `Connection::fetchColumn()` signature where the 3rd argument is now `$types`, not `$columnIndex`.

[DBAL-2958] Replaced extension of \PDOStatement with a composition to avoid having to replicate the \PDOStatement interface in ResultStatement

Internally, ArrayStatement expects every row to be represented as an array regardless of the fetch mode, however FetchMode::COLUMN produces one value per row.

- Fixed docblocks
- Removed return statements on void methods
- Cleaned up unused private / local variables
- Fixed license issues
- Removed SVN leftovers
- Fixed doctrine-project.org links
- Added line breaks before return statements

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.