renamed display to output

src/cc3k.cc

@@ -3,7 +3,7 @@
 #include "constants.h"
 
 CC3K::CC3K(const feature enabled_features,
-           input *in, display *out, RNG *rng):
+           input *in, output *out, RNG *rng):
         enabled_features{enabled_features},
         in{in}, out{out}, rng{rng} {
         curr_menu = std::make_unique<menu>(enabled_features);