Big patch for mcview

[Roland Illig]

Jindrich Makovicka wrote:
> Crashes when switching between viewer modes. To reproduce, use F3 on a 
> jpg/mp3/whatever (assuming you have mpg123, ImageMagick or other 
> corresponding viewer), press F8 to display raw, then press F4 => sig11.

I cannot reproduce this. Can you be more specific where mc crashes? (a 
backtrace of an mc with CFLAGS=-ggdb would be most helpful)

Roland