Adding an "hide_empty" parameter on wp_nav_menu() function

[prionkor]

There should be a hide empty parameter on wp_nav_menu() function argument as there is no point to echo a empty menu item.

1. The node with submenu should be skipped.
2. May be false by default.
3. There will be a check box on side of the menu (check attached image)

4. The "hide_empty" parameter will be overwrite by that checkbox. That means the user choice will have more priority then theme developers choice.

The checkbox will apply on taxonomy.