Reference and build from tildeio/rsvp.js and remove amd

Similar to https://github.com/emberjs/ember.js/pull/5216, this PR removes the RSVP AMD and instead uses bower to pull in the es6 files then in the Brocfile put them into the pipeline to be finalized.

This should make it considerably easier to upgrade rsvp as well as play into future plans for using the bundled output for the es6 module transpiler (by having all inputs in es6). [discussed with @rwjblue]

_IMPORTANT_ __(v3.0.7 -> v3.0.10)__

The version of RSVP installed via bower is [here](https://github.com/tildeio/rsvp.js/commit/ca08b69b65c34089a55ed6ec194d5cac0b867688) which is version 3.0.10.  

The current AMD (that is removed in this PR) is [3.0.7](https://github.com/emberjs/ember.js/pull/4972) so this should be kept in mind while reviewing this PR.  

Cheers :)