Optimize GC for enumeration in context cascade insertion.

Assets/Cryville/Crtr/PdtEvaluator.cs

@@ -126,7 +126,7 @@ namespace Cryville.Crtr {
 		public void ContextCascadeInsert() {
 			ContextCascade[_cascadeHeight++].Clear();
 		}
-		public void ContextCascadeInsert(IReadOnlyDictionary<int, PropSrc> srcs) {
+		public void ContextCascadeInsert(IntKeyedDictionary<PropSrc> srcs) {
 			ContextCascadeInsert();
 			foreach (var src in srcs) ContextCascadeUpdate(src.Key, src.Value);
 		}