Cleanup naming & order in admin controller

no issue

 There seemed to be no convention or order to the functions in the admin controller, so I have:
 - organised them
 - reordered them
 - added a small doc-block
 - reordered some routes
 - updated tests accordingly
ReadMe Improvements

SEMANTICS ALL UP IN THIS WHAT
Merge pull request #2258 from ErisDS/admin-ctrl-cleanup

Cleanup naming & order in admin controller
Rename client -> clientold

issue #2271

- should allow development of new admin UI whilst still having access to the old ui
Merge pull request #2274 from ErisDS/ember-rename

Rename client -> clientold
Create base route for ember admin
Add basic template for Ghost admin in Ember

Inspired and derived from:

https://github.com/taras/Ghost/compare/ember-admin
https://github.com/manuelmitasch/ghost-admin-ember-demo
https://github.com/stefanpenner/ember-app-kit