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
Document Priming References and hydration

Updated to explain potential pitfall with disabling hydration while enabling primed references.

Fixes #800
Merge pull request #814
Support filter parameters in Configuration
Clean up filter doc blocks in Configuration
Ensure BsonFilter::$parameters is initialized
Merge pull request #908
Rename array key for filter class option in Configuration
Document filter class usage and configuration (fixes #899)
Merge pull request #913 from doctrine/filter-docs

Document filter class usage and configuration
Update inheritance-mapping.rst

"discriminatorMap: type" -> "discriminatorField: type"
Merge pull request #923 from ZCJ/master

Update inheritance-mapping.rst
Test to prove, that when calling merge twice on the same detached document a spl_object_hash collision occurs.
Detach old managed copy as no more references on it