Remove unused code

As far as I can tell, this went out of order in 2009.2a-153-g01e03a7
with a later rename from `position` to `item` in 2011.3-817-g27227ff and
has been a lone 0 ever since.
Reformat
Do not include message text in _IngameMessage.__repr__

That text can be unicode often enough to reliably crash printing a
message for debugging purposes. Instead, add __unicode__ so that
`unicode(m)` will provide that information.
Attempt to prevent crashes as reported in #2273

Pending further information on reproducing or otherwise tracking down
the problem, this should at least stop the game crashing for something
"minor" as a messagewidget hickup.