Flake: slight optimisation for new window functions (partial_tukey, punchout_tukey).

CUETools.Codecs.ALAC/WindowMethod.cs

@@ -4,6 +4,8 @@
     {
         Estimate = 0,
         Evaluate = 1,
-        Search = 2
+        Search = 2,
+        EstimateN = 3,
+        EvaluateN = 4,
     }
 }