Consolidate SimpleAuth.AuthenticatedRouteMixin into AuthenticatedRoute

No issue
Peg node-sass dependency to 1.0.3.

No Issue.
- grunt-sass has node-sass as a dependency (^1.0.0) but the build
  requirements of node-sass version 1.1.0 have changed and will
  fail without a newer version of the gnu compilers.
Merge pull request #4355 from jaswilli/deps-sass

Peg node-sass dependency to 1.0.3.
Added screenshot to readme
Merge pull request #4351 from novaugust/authenticated-route

Consolidate SimpleAuth.AuthenticatedRouteMixin into AuthenticatedRoute
Redirect unauthorized users to signin from debug

Closes #4357
- Adds a call to `this._super()` in DebugRoute#beforeModel to hit the ember simpleauth mixin's beforemodel hook
Merge pull request #4358 from novaugust/unauthed-debug-redirect

Redirect unauthorized users to signin from debug
File structure cleanup
Var cleanup
Better comments

Also introduces a new format of file opening comment, to outline what happens and a contents list.