Stay on posts.index route when no posts exist

No Issue
Merge pull request #3104 from jaswilli/route-undefined

Stay on posts.index route when no posts exist
Add off as a noop function to touch editor.

Closes #3107
Merge pull request #3108 from novaugust/touch-editor-off

Add off as a noop function to touch editor.
New setup screen for blog installation.

fixes #3072
- Change router to handle /ember/setup/
- Adjust doSignup to also handle setup
- Adjust tests and add new where necessary
- Add setup controller, setup validation, setup route
- Adjust casper emberSetup to handle new setup