Implement SQL Anywhere driver exception conversion

This fixes the SQL Anywhere driver to implement the new exception conversion.
The `ExceptionTest::testConnectionException()` test still fails though as exceptions occurring during connect are thrown in `Connection::connect()` which is not caught and transformed into a wrapped `DBALException`. I feel like this is an implementation error in either `Connection` or a false assumption in `ExceptionTest::testConnectionException()`. At least I think this is not a driver problem. Maybe there should be a `DBALException::driverExceptionDuringConnect()` that is called if an exception is raised in `Connection::connect()`.