managedObject retrieved from managedObjectCache could be deleted.
fixed that related objects that are getting deleted (cascade) do not get propagated the isDeleted. So they get deleted but no new objects are created for them so they end up being nil after second mapping.
Merge branch '#1802addition-isDeleted-is-not-propagated-to-related-objects' into isDeleted-propagation-bug

Conflicts:
	RestKit.xcodeproj/project.pbxproj
Merge pull request #1 from BObereder/isDeleted-propagation-bug

Is deleted propagation bug