Require $platform in AbstractSchemaManager::__construct()

Replace DefaultExceptionConverter with driver-specific implementations

Mark driver classes final

PDO connection and statement classes made final

Mark result constructors internal

Move the logic of driver exception conversion into a separate interface

Expect only DriverException from Result::fetch*() methods

Remove irrelevant references to PDO from the documentation

Missing driver exception annotations

The situation reported as an exception is unlikely to happen and there's no test that reproduces it.

Remove ExceptionConverterDriver

Remove PingableConnection

Remove deprecated driver classes