[make entry points square in grin graph
John Meacham <john@repetae.net>**20060430003854] hunk ./Grin/Show.hs 170
-    fnode (x,_ :-> e) = [("label",show x)] ++ if hasError e then [("color","red")] else []
+    fnode (x,_ :-> e) = [("label",show x)]
+        ++ (if hasError e then [("color","red")] else [])
+        ++ (if x `elem` grinEntryPoints grin then [("shape","box")] else [])