Fixed redundancy in some test case suites
Fixed issues in SocialServicesRelation class => some code remained after splitting the CRERemoteBindingRelation
Added new NumberDate transformer and modified negate transformer
Fixed an issue in isNilTransformer and added unit test for the remaining transformers
Fixed date transformer test
Split BindKitTests in two suites
Moved all error messages to a plist file from NSError+CREBinder and cleaned the assertions