Fix undefined index error recomputing changesets for documents without one
Rewrite #897 fix and test to be consistent with ORM

This makes the test more in line with the corresponding ORM fix in doctrine/doctrine2@d473824279bfee19772bb1692d2a3453a2aff233. Our lifecycle callbacks to not yet receive event arguments, so the DocumentManager must be injected into the document manually (yes, this is a hack).
Merge pull request #897
Ensure "cascade" mapping is set for ResolveTargetDocumentListener

ResolveTargetDocumentListener expects $mapping['cascade'] to be set, while it previously may not have been depending on how the ClassMetadata was defined (the "isCascade*" fiels were always set).

This also makes the cascade handling consistent with ORM.
Merge pull request #888
Add ResolveTargetDocumentListener section to 1.0.0-BETA10 changelog
Update changelog for 1.0.0-BETA11