Changes

fixes: 8921 deprecated gtDisplayString
- first no more users of gtDisplayString.
- second (next commit - check all the implementors and deprecated them).

rewrote all the gtDisplayOn: as displayStringOn:
- next step should be 
-- remove gtDisplayOn: methods since they are not called anymore.
-- check class redefining displayString because they should redefine displayStringOn: instead
-- check stupid displayStringOn: that could be just doing the same than their superclass
-- avoid that displayStringOn: use displayString (because we do not need to create yet another stream boy! - and kasper already fixed all the printOn: so now that the system is clean
we should continue to have it clean!!!!!!).

Fixing String

Now displayStringOn: is packaged on the class and not in an extension
+ definitionString

Force against the displayStringOn: to be published. (add a silly comment).

Make sure that there is no senders of gtDisplayOn: anymore.

Fixing the conflict.