- make repeatable for keys and joystick buttons default to false

rather than true; it's too confusing for users if keys and buttons
  repeat by default (keys weren't anyway, but they were supposed to)

src/Input/input.hxx

@@ -202,7 +202,7 @@ private:
    */
   struct button {
     button ()
-      : is_repeatable(true),
+      : is_repeatable(false),
 	last_state(-1)
     {}
     bool is_repeatable;