[GREENFOOT-39] Objects from the world as parameters for methods

When a method call requires a parameter it should be possible to select an object from the object world as parameter.

At the moment this is possible with a few quirks:

invoke the inspector menu of the object that should be passed as parameter in order to find the name of the object
type in the name of the obejct in the method call dialog

In greenfoot the user doesn't work with object names as in BlueJ and therefor the above solution is not good.

Instead, it should be possible to click on the object that should be the parameter. Not sure what should be shown in the method call dialog after an obejct has been clicked \- the image of the object maybe (what if we have several objects of the same class) ?

Objects do not have names in greenfoot!

When clicking an object it should show an icon representing the object. This icon should be treated as any other character in the textfield of the method invocation dialog.

The icon should show the image for the object if it is an actor. Possibly with the location overlayed.

If it is a non-actor object it should just show a red blob (BlueJ-style object, but without name). This will be needed so rarely that it doesn't really matter that you can't distinguish objects of the same class.

Step 1 of this is now done: It now shows the name of the object in the dialog like in BlueJ

Step 2 is to show the icon.

Issue metadata

Issue type: Task
Priority: Low