Add count buffer to keys_getch()

Key commands can be prefixed with a natural number - keys_getch() will
store this number in the buffer pointed to by the second parameter. Set
this parameter to NULL to disable count prefixes.

Signed-off-by: Lukas Fleischer <calcurse@cryptocrack.de>

src/calcurse.c

@@ -186,7 +186,7 @@ main (int argc, char **argv)
           wins_reset ();
         }
 
-      key = keys_getch (win[STA].p);
+      key = keys_getch (win[STA].p, NULL);
       switch (key)
         {
         case KEY_GENERIC_REDRAW: