Windows users who may not have a middle button at all, but I've
replicated it in GTK to maintain cross-platform consistency.
[originally from svn r4166]
as an alternative control method in Cube. (This was a bit of hassle
in the Windows front end; I also introduced a debugging framework
and made TranslateMessage conditional.)
[originally from svn r4162]
are now expected to provide a list of `presets' (game_params plus a
name) which are selectable from the menu. This means I can play
both Octahedron and Cube without recompiling in between :-)
While I'm here, also enabled a Cygwin makefile, which Just Worked.
[originally from svn r4158]
