fix style and add var declaration

src/colorspace.js

@@ -376,9 +376,9 @@ var DeviceCmykCS = (function DeviceCmykCSClosure() {
       y = (y * (1 - k) + k);
 
       // CMY -> RGB: http://www.easyrgb.com/index.php?X=MATH&H=12#text12
-      r = (1-c);
+      var r = (1 - c);
-      g = (1-m);
+      var g = (1 - m);
-      b = (1-y);
+      var b = (1 - y);
 
       return [r, g, b];
     },