spec: Centralize circular load prevent code
Fix bulk clipping import

I didn't think it was possible to test this, so I didn't, and it
inevitably boke.  Turns out it's easy to test and easy to fix.

Many thanks to the test who reported this.  I'd use your handle here,
but I don't know whether you prefer credit or privacy. :-)
Correct Ember source versions used by Emblem

This prevents asset build errors in production:
https://github.com/machty/emblem.js/issues/107