Turn ember-hypermedia into a proper package/library

[plexus]

To consume our Yaks API we've been using some custom Ember code that turns the HAL responses into Ember models, and that allows you to follow links and submit forms, which then returns a promise, as you would expect in ember land.

This is pretty cool, and "works for us", but it's something people seem to be interested in, but unlike Yaks it's not actually open sourced in any nice way.

As a starting point I pushed the relevant code into its own repo, ember-hypermedia, so people can already have a look how we do it, and so it can hopefully evolve into a general purpose lib.

TODOs

• convert coffee to ES6
• add bower/npm config
• make sure it actually works in an ember app
• take out the references to Ticketsolve specific stuff
• add test coverage

Bonus points

• introduce a format-specific adapter layer
• implement more formats

cc @bjoska @mpedrera