[DBAL-722] Introduce subclasses for runtime relevant exceptions (NotNull, DuplicateKey, ForeignKey Constraint Violation).

- 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

Fixed a PHP warning in DBALException::driverExceptionDuringQuery() when a parameter contains binary data.

[DBAL-178] Fixed an undescriptive error message and a problem when using custom types and their reverse engineering from the database. Allows Type#getMappedDatabaseTypes() to be implemented in custom types, mapping to vendor database types during reverse engineering.

[2.0] DDC-92 - Refactored Doctrine\DBAL\DriverManager some more in regards to exceptions and added some more test-cases.

[2.0] DDC-92 - Removed DoctrineException from Doctrine\DBAL\DriverManager and replaced with more specific DBALException's

[2.0][DDC-22] Fixed. Also cleaned up association handling. More to come: exception refactorings, proxy simplifications (single proxy class, not two).