removing WXWIN_COMPATIBILITY_2_4 -- call for volunteers

[Vadim Zeitlin]

 Hello,

 Would anyone have time to remove code inside #if WXWIN_COMPATIBILITY_2_4
tests? This should be pretty trivial to do as the code should just be
deleted but it still takes time as it needs to be done carefully and
manually and tested afterwards. This is, of course, not urgent but I think
it would be nice to get rid of at least some old code instead of just
keeping adding new stuff.

 TIA,
VZ