The `PostgreSqlPlatform`, `SQLAnywherePlatform` and `SQLServerPlatform` classes have been renamed to `PostgreSQL94Platform`, `SQLAnywhere16Platform` and `SQLServer2012Platform` respectively.

When deprecating an old platform version, we can deprecate and later remove a specific class. Otherwise, there's no way to express the deprecation on the class level and the upgrade notes contain sentences like: "`XYZPlatform` and `XYZKeywords` now represent XYZ (version)".

Extract Doctrine\DBAL\DBALException::notSupported()
Extract Doctrine\DBAL\DBALException::invalidPlatformVersionSpecified()
Extract Doctrine\DBAL\DBALException::invalidPdoInstance()
Extract Doctrine\DBAL\DBALException::invalidWrapperClass()
Extract Doctrine\DBAL\DBALException::invalidDriverClass()
Extract Doctrine\DBAL\DBALException::invalidTableName()
Extract Doctrine\DBAL\DBALException::noColumnsSpecifiedForTable()
Extract Doctrine\DBAL\DBALException::typeExists()
Extract Doctrine\DBAL\DBALException::typeAlreadyRegistered()
Extract Doctrine\DBAL\DBALException::typeNotRegistered()
Extract Doctrine\DBAL\DBALException::unknownColumnType()
Extract Doctrine\DBAL\DBALException::typeNotFound()
Extract Doctrine\DBAL\DBALException::invalidPlatformType()
Extract Doctrine\DBAL\DBALException::driverRequired()
Extract Doctrine\DBAL\DBALException::unknownDriver()
Extract Doctrine\DBAL\DBALException::invalidColumnIndex()
Extract Doctrine\DBAL\Exception\ConnectionException::commitFailedRollbackOnly()
Extract Doctrine\DBAL\Exception\ConnectionException::noActiveTransaction()
Extract Doctrine\DBAL\Exception\ConnectionException::savepointsNotSupported()
Extract Doctrine\DBAL\Exception\ConnectionException::mayNotAlterNestedTransactionWithSavepointsInTransaction()
Extract Doctrine\DBAL\Exception\InvalidArgumentException::fromEmptyCriteria()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailed()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailedFormat()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailedInvalidType()
Extract Doctrine\DBAL\Type\ConversionException::conversionFailedSerialization()
Extract Doctrine\DBAL\Query\QueryException::unknownAlias()
Extract Doctrine\DBAL\Query\QueryException::nonUniqueAlias()
Extract Doctrine\DBAL\Sharding\ShardingException::notImplemented()
Extract Doctrine\DBAL\Sharding\ShardingException::missingDefaultFederationName()
Extract Doctrine\DBAL\Sharding\ShardingException::missingDefaultDistributionKey()
Extract Doctrine\DBAL\Sharding\ShardingException::activeTransaction()
Extract Doctrine\DBAL\Sharding\ShardingException::noShardDistributionValue()
Extract Doctrine\DBAL\Sharding\ShardingException::missingDistributionType()
Extract Doctrine\DBAL\Cache\CacheException::noCacheKey()
Extract Doctrine\DBAL\Cache\CacheException::noResultDriverConfigured()
Extract Doctrine\DBAL\Schema\SchemaException::tableDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::indexNameInvalid()
Extract Doctrine\DBAL\Schema\SchemaException::indexDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::indexAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::columnDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::namespaceAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::tableAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::columnAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::sequenceAlreadyExists()
Extract Doctrine\DBAL\Schema\SchemaException::sequenceDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::uniqueConstraintDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::foreignKeyDoesNotExist()
Extract Doctrine\DBAL\Schema\SchemaException::namedForeignKeyRequired()
Extract Doctrine\DBAL\SQLParserUtilsException::missingParam()
Extract Doctrine\DBAL\SQLParserUtilsException::missingType()
Drop Doctrine\DBAL\DBALException::invalidPlatformSpecified()
Drop Doctrine\DBAL\DBALException::limitOffsetInvalid()
Drop Doctrine\DBAL\Schema\SchemaException::alterTableChangeNotSupported()

- 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.