minor performance tweak in the cascade code
Add test for check remove with more child level
fixed handling of proxies in UnitOfWork::purgeChildren
updated tests to new bin file name
Merge pull request #225 from doctrine/patch-1

fixed handling of proxies in UnitOfWork::purgeChildren
Allow selection of extending documents

- Adds new multivalue node type property phpcr:classparents
- Popualtes this with the class names of ALL extending classes on
  persist
- QueryBuilder selects on phpcr:class OR phpcr:classparents
Refactored a little and added test.
Fixes some text
Refactored to get parent classes from ClassMetadata