refactor(main): init keys table with hardcoded "false" instead of cur…

…rent fenster->keys value

Same result but less CPU usage

spec/main_spec.lua

@@ -564,6 +564,7 @@ describe('fenster', function()
 			local index = 0
 			while window.keys[index] ~= nil do
 				assert.is_boolean(window.keys[index])
+				assert.is_false(window.keys[index])
 				index = index + 1
 			end
 			assert.is_equal(index, 256)

src/main.c

@@ -184,7 +184,7 @@ static int lfenster_open(lua_State *L) {
   // initialize the keys table and put it in the registry
   lua_createtable(L, KEYS_LENGTH, 0);
   for (int i = 0; i < KEYS_LENGTH; i++) {
-    lua_pushboolean(L, p_fenster->keys[i]);
+    lua_pushboolean(L, 0);
     lua_rawseti(L, -2, i);
   }
   lua_pushvalue(L, -1);  // copy the keys table since luaL_ref pops it