Fix a typo in code example

objectRequesOperationWithRequest ->
objectRequestOperationWithRequest
Merge pull request #1182 from darashi/fix-typo-in-readme

Fix a typo in code example
Add missing copy support for the entity and deletion predicate. closes #1184
Fix potential crash due to serious Core Data error from failing to obtain a permanent objectID for an object that was just saved to the persistent store, but whose `objectID` is stale. fixes #1183
Tweak docs, add test cases for mapping a response with a descriptor that does not specify any attributes/relationships
Add support for obtaining a permanent managed object ID for the `targetObject` of an `RKManagedObjectRequestOperation`
Unwind earlier fix for obtaining permanent objectID for targetObject in favor of the overridden setter on RKManagedObjectRequestOperation