adding port doc for universe from world

svn: r17606

collects/teachpack/2htdp/scribblings/port.scrbl

@@ -2,7 +2,7 @@
 
 @(require "shared.ss" 
 	  "port.ss"
-	  scribble/manual
+	  scribble/manual 
           (for-label scheme
                      (prefix-in htdp: teachpack/htdp/world)
 		     (prefix-in 2htdp: teachpack/2htdp/universe)
@@ -185,6 +185,29 @@ The most important change concerns the lines that launch the world program:
 
 key events and mouse events are string: use key=? and mouse=? 
 
+stuff from Todd: 
+
+I'm not actually worried about me--I try to stay up to date, and I
+teach three intro classes, so enough of my time is devoted to the HtDP
+languages that I can stay on top of things. I'm worried about people
+like Renee Ciezki in Arizona who pushes other teachers in her county
+to use HtDP only to discover that the lessons she's given them to use
+don't quite work anymore. At least she emails and asks what's going
+on--I'm afraid other people just throw up their hands in frustration.
+
+And it's not just that one change to go from world to universe--key
+events became strings instead of symbols, for example, and there are a
+number of other small changes. Having a checklist that explains how to
+get from X to Y would make the transition less complicated.
+
+Also, being unable to show previous student projects as examples is a
+major downer. It's incredibly motivational to current students to see
+what previous students have done. Porting five or six old projects to
+the new version can eat up a couple of hours if you have to run them
+and just correct errors. That's not horrible unless you don't have a
+couple of hours to do it.
+
+
 @; -----------------------------------------------------------------------------
 @section{Porting Image Programs}