Use a wrapped PDO Statement instead of a custom class for `pdo_sqlsrv` since `PDOSqlsrv\Statement` doesn't extend `PDOStatement` anymore.

The test is partially skipped due to:

1. Fetching blob as binary string from pdo_sqlsrv requires using `PDOStatement::bindColumn()` and `PDOStatement::fetch(PDO::FETCH_BIND)` which are not supported by the DBAL.
2. Setting encoding on the connection level is not supported: https://msdn.microsoft.com/en-us/library/ff628164(v=sql.105).aspx

- 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 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.

Signed-off-by: Juozas Kaziukenas <juozas@juokaz.com>

Signed-off-by: Juozas Kaziukenas <juozas@juokaz.com>