[native menus] Edit menu needs Undo, Cut, Copy, and Paste items

[gruehle]

The Windows menus never had these. Mac used to have Cut/Copy/Paste, but those have been removed temporarily.

We need to add these items in for both platforms.

[peterflynn]

@gruehle this is out of scope for Sprint 19 though, right? (Since the HTML menus didn't have these items).

[gruehle]

Correct - which is why I didn't tag it as Sprint 19 :-)

[peterflynn]

Good point :-)

[gruehle]

Reviewed. Set to Sprint 19, but will move out if it is too complicated.

[gruehle]

Fixed in #2564.