Revisit MenuLayer wraparound change (#145)

[jwise]

@Katharine notes that #145 perhaps ought to be opt-in for apps. We probably ought to revisit this at some point in the future...

[Katharine]

To clarify for the mysterious future when someone looks at this issue, by "opt in" I mean "opt in by building against the hypothetical Rebble SDK", not (necessarily) by making it a flag they can actively control.

If there is an explicit API for it, it should probably default on for apps built with the appropriate SDK. I'd probably not expose it at all, though.

[jwise]

Yeah, I think classically the way Pebble has handled this is by having the init routine change name. We could do that too. You know, in the Rebble SDK future.