MenuBar: Support Title so that a Window (with wasteful border) is not needed to show app title

[tig]

Something like this:

But, make it obvious that "Notepad" is not part of the menu.

Perhaps right align the title? Might be weird.

Perhaps, a different color?

Perhaps, a different background color?

Perhaps, just a dash after? (Notepad -)?

[tznind]

What about something like this:

The layout would need to be:

Align center (as above) unless:

• If menus fill whole horizontal space then hide title
  

• If menus go past half way (i.e. would overlap title) then align title right instead of center
  

[tznind]

Perhaps, just a dash after? (Notepad -)?

Adding dashes does look pretty cool. Probably should be optional or just a convention we use in UICatalog (i.e. Title="-mytitle-") and recommend.

[tig]

Great ideas @tznind -

FWIW, while I should be working on higher-priority stuff, I sucked myself into the Menu and MenuTests code yesterday. I am doing a major refactoring of the tests because they are super fragile. This will (hopefully) enable updating a bunch of this stuff easily.

[tig]

Closing. This will be addressed in #2975