Merge pull request #2404 from emberjs/fix-travis-for-handlebars-2.0

load handlebars 2.0 for canary
Update model.js

Add documentation of the fact that reloading a model will fulfill with the reloaded model.
Merge pull request #2406 from kategengler/patch-1

Update model.js
Update explanation on how to run tests in browser
Merge pull request #2410 from BookingSync/update-contributing

Update explanation on how to run tests in browser
Add `createRecord` to PromiseArray so it proxies to ManyArray
Merge pull request #2411 from BookingSync/proxy-create-record-on-has-many

Add `createRecord` to PromiseArray so it proxies to ManyArray
refactored into server methods
split relationship files
remove recordArrayManager from hasMany