(explicit) kernel methods in TensorFlow.

## Bug Fixes and Other Changes

*   In python, `Operation.get_attr` on type attributes returns the Python DType
    version of the type to match expected get_attr documentation rather than the
    protobuf enum.
*   tensorflow/contrib/rnn undergoes RNN cell variable renaming for consistency

		{"GetsockoptInt", Func, 0},
		{"GetsockoptUcred", Func, 1},
		{"Gettid", Func, 0},
		{"Gettimeofday", Func, 0},
		{"Getuid", Func, 0},
		{"Getwd", Func, 0},
		{"Getxattr", Func, 1},
		{"HANDLE_FLAG_INHERIT", Const, 0},
		{"HKEY_CLASSES_ROOT", Const, 0},
		{"HKEY_CURRENT_CONFIG", Const, 0},
		{"HKEY_CURRENT_USER", Const, 0},
		{"HKEY_DYN_DATA", Const, 0},

    MutableOperandRange getArgOperandsMutable() {
      return getArgsMutable();
    }

    // Returns the callee of this operation.
    CallInterfaceCallable getCallableForCallee() { return getFAttr(); }
    // Sets the callee from the callable.
    void setCalleeFromCallable(CallInterfaceCallable callee);

    // returns the callee of this operation.
    func::FuncOp func() {