[WIP] Implement new popovers

No issue

Implements a new popover component (not to be confused with what are now called dropdowns [menus])

Todo:

- [x] Emberify
- [ ] Get checked over by people with Über Ember skilz

Very probably. That, however is a bit beyond me. =/ Managing the state so it can be clicked or hovered (so the popover doesn't close when mouse out, even if you clicked to open it) is something I'll need to learn.