Format object descriptions like object literals.

This change makes CPDictionary descriptions exactly like Objective-C literals. Later when Objective-J adds support for such literals too, it'll be possible to just copy and paste a CPDictionary description into code.

Also updated CPArray to look similar for consistency.

Foundation/CPArray/_CPArray.j

@@ -874,7 +874,7 @@ var concat = Array.prototype.concat,
 {
     var index = 0,
         count = [self count],
-        description = "[";
+        description = "@[";
 
     for (; index < count; ++index)
     {

Foundation/CPDictionary.j

@@ -651,7 +651,7 @@
         var key = keys[index],
             value = self.valueForKey(key);
 
-        string += "    " + key + " = " + CPDescriptionOfObject(value).split("\n").join("\n    ") + ";\n";
+        string += "    @\"" + key + "\": " + CPDescriptionOfObject(value).split("\n").join("\n    ") + (index + 1 < count ? "," : "") + "\n";
     }
 
     return string + "}";