lualoader: Add "menu.default", initialized to menu.welcome

The intent here is to abstract away the name of the default menu. The
default menu is still the welcome menu, but this detail doesn't need to
matter to things outside of the menu module. You may change the default
menu, but one would need to modify a specific menu.

stand/lua/menu.lua

@@ -327,6 +327,8 @@ menu.welcome = {
 	},
 }
 
+menu.default = menu.welcome
+
 function menu.run(m)
 
 	if menu.skip() then
@@ -335,7 +337,7 @@ function menu.run(m)
 	end
 
 	if m == nil then
-		m = menu.welcome
+		m = menu.default
 	end
 
 	-- redraw screen
@@ -351,7 +353,7 @@ function menu.run(m)
 
 		-- Special key behaviors
 		if (key == core.KEY_BACKSPACE or key == core.KEY_DELETE) and
-		    m ~= menu.welcome then
+		    m ~= menu.default then
 			break
 		elseif key == core.KEY_ENTER then
 			core.boot()
@@ -387,7 +389,7 @@ function menu.run(m)
 		end
 	end
 
-	if m == menu.welcome then
+	if m == menu.default then
 		screen.defcursor()
 		print("Exiting menu!")
 		return false