Refactor representation of character category in PDT.

Assets/Cryville/Crtr/Skin/SkinInterpreter.cs

@@ -79,7 +79,7 @@ namespace Cryville.Crtr.Skin {
 			}
 		}
 		object InterpretAnimationSpanKey() {
-			if ((ct & 0x0040) != 0 || cc == ',') {
+			if ((ct & CharCategory.Digit) != 0 || cc == ',') {
 				float start = 0, end = 1;
 				if (cc != ',') {
 					start = float.Parse(GetNumber());