Refactor for AB4

src/Drawable.java

@@ -1,10 +1,13 @@
 import codedraw.CodeDraw;
 
-// An object that can be drawn in a CodeDraw canvas.
-//
+/**
+ * An object that can be drawn in a CodeDraw canvas.
+ */
 public interface Drawable {
 
-    //draws the object into the canvas 'cd'
-    //Precondition: cd != null
+    /**
+     * draws the object into the canvas 'cd'
+     * Precondition: cd != null
+     */
     void draw(CodeDraw cd);
 }