I am not sure if there is a rationale behind ignoring extra keys like
this. I was under the impression that something might copy options to
platform specific options, thus leaving options in the original array,
knowing they would be ignored anyway. If it is the case, it would be
best to just move them, otherwise, this commit might help troubleshoot
some mapping issues.
I had to fix some tests that wrongly used that options array (maybe
these options were valid at some point?).

[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

[2.0][DDC-237][DDC-216] Fixed. If you're using manual proxy generation through the CLI, please regenerate your proxies.

[2.0][DDC-164][DDC-165] Fixed. Cleaned up ManyToManyMapping. Cleaned up identifier handling and handling of composite identifiers in some places.

[2.0][DDC-49][DDC-50][DDC-33] Fixed DDC-49 and DDC-50. Also addressed DDC-33. Various other small changes and fixes. For problems with proxy objects please refer to the updated documentation.