Unescaping re-added, support limited to schema introspection (#2850 will bring more complete coverage)

@morozov review: According to MySqlPlatform::getListTableColumnsSQL(), the default column is always selected. Removed ??

- 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

Unsigned column properties were never set. In consequence all migrations diff were trying to change the column definition when it was already changed.

[DBAL-220] Add support for Index flags and implement support for SQL Server CLUSTERED/NONCLUSTERED and MySQL FULLTEXT.

[DBAL-42] Add support to reverse engineer Comments from MySQL, PostgreSQL and ORacle into Doctrine\DBAL\Schema\Column instances and added comment comparison into Comparator.

Apply array_change_key_case in MysqlSchemaManager::_getPortableColumnDefinition() and adapt further code to work with it

Fixed a problem in PostgreSql AutoIncrement Detection, changed Autoincrement API for platform/schema manager interaction a little bit

Added registerDoctrineMappingType() and getDoctrineMappingType() methods, converted DB2 platform and added some tests, made all platforms work for now

Support Sqlite

Migrated MySQL to Doctrine Type Map

Fixed nasty bug in testcase

Migrated Postgres to support Doctrine Mapping Types

Refactored Oracle Platform to support Doctrine Mapping Types

Refactored DB2 support for Doctrine Mapping Types a little bit