Prints sqrt, but ugly ..

Important changes and remarks:

1) Responsibility of creating Canvas and Graph to Controller (I suggest changing name to sth like MainController)

2) I see graphs as children of Canvas in Actor hierarchy. It's done but ugly, current implementation doesn't support this idea

3) Some graph parameters are temporarily hardcoded in Canvas .. It's bad but waits for better times

4) TestActor and TestProps are no longer used

5) I suggest not reprinting every point in every update .. That's very bad for performance