…ic type parameters. This commit comprises only those changes required in the core of JUnit -- basically adding a validator that the Theories runner can call to reject theories with generic type variables (that are hard to resolve), and deprecating FrameworkMethod#producesType, which only the Theories runner uses, and which will be supplanted by an equivalent method on ParameterSignature. Other required changes will be added to the Theories experiment once it migrates over to junit.contrib.

…ucesType. Adding acknowledgements entry for pholser. Starting 4.9.1 release notes.