Set 1 player mode

Disable second player with define.

src/main.cpp

@@ -1,7 +1,7 @@
 #include "spawn.h"
 #include "intToStr.h"
 
-#define NB_GAMERS 2
+#define NB_GAMERS 1 // Can be 1 or 2
 
 #define NB_GROW 6
 #define NB_BASE 10