remove grunt, use testem and broccoli, build ember-inflector from bower

This will need to be extracted to some sort of ember-cli blueprint. I'll be working on that.

cc @rwjblue
In ember.js we are using ember-cli to do the things.  Is there a particular reason for using broccoli instead of ember-cli?  Either is fine, I'm just not sure about the rationale either way.  ;)