implement full NSMenu and NSMenuItem APIs

[lunixbochs]

[lunixbochs]

what's the convention for handling overlapping selectors? do we just delete all but one if they're compatible?

   = note: candidate #1 is defined in an impl of the trait `NSMenu` for the type `*mut objc::runtime::Object`
346   = note: candidate #2 is defined in an impl of the trait `NSMenuItem` for the type `*mut objc::runtime::Object`
347   = note: candidate #3 is defined in an impl of the trait `NSWindow` for the type `*mut objc::runtime::Object`
348help: disambiguate the associated function for candidate #1
349   |
35079 |     NSMenu::setTitle_(window, title);
351   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
352help: disambiguate the associated function for candidate #2
353   |
35479 |     NSMenuItem::setTitle_(window, title);
355   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
356help: disambiguate the associated function for candidate #3
357   |
35879 |     NSWindow::setTitle_(window, title);
359   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
360
361

Edit: Ahh, no, deleting redundant ones doesn't work very well, because you might not be importing the other traits :/

Is there any better answer here than making this a breaking change?

[bors-servo]

:umbrella: The latest upstream changes (presumably b009c87f2da0038bb474800cd88597843e5dbdae) made this pull request unmergeable. Please resolve the merge conflicts.

[lunixbochs]

it's been 15 months, I assume if someone wanted to merge this they would have by now