[WIP] Update Ember example

[dougestey]

This updates the Ember example in the repo to Ember 3, and resolves #69

Note that this gets rid of the use of bower, which changes the way we import single-spa-ember. Instead of directly pointing EmberCLI to the AMD loader, I resorted to using ember-auto-import.

Needs some semantic cleanup, but it builds and runs. :)

[joeldenning]

The single-spa core team is considering killing this repo entirely, since it often leads to more confusion than value. Which is why I've been slow to review this. However, I'll merge this in for now as the single-spa core team decides what to do with it.