sync router.js fixes App#reset in ember-testing issue

https://github.com/tildeio/router.js/commit/e605ffc063334c9ba5a8ff112b009d5f7180b7de
Fixed bug with promises on startup. Fixes #2756.

This bug would cause your app to break if you refreshed
the page on a route the returned a promise in `model`.
Merge pull request #2759 from machty/promise-startup-fix

Fixed bug with promises on startup. Fixes #2756.
Remove ember-testing from production build
Merge pull request #2761 from teddyzeenny/ember-testing-build

Remove ember-testing from production build
adding docs for Ember.beforeObserver
Adds assertion for misnamed controller name provided to render helper. fixes #2385
Merge pull request #2765 from twokul/master

adding docs for Ember.beforeObserver
Added assertion for incorrect container lookup names
Merge pull request #2769 from sebastianseilund/normalize-assertion

Added assertion for incorrect container lookup names
Fix assertion, arguments.length should be less than 2
Fix typo
Merge pull request #2778 from bradfol/action-docs

Action helper docs
Merge pull request #2777 from bradfol/handlebars-helper-assert

Fix assertion for Ember.Handlebars.helper
update ember-dev
bump ember-dev
Add new backburner build

cc @stefanpenner @kagemusha
Version bump - 1.0.0-rc.5
correctly prepare starter kit during release tooling
don't forget to update the website during release preparation