Update Ember to latest stable (1.7.0).
Rework editor save button.

Refs #3834
- Change bindings and fix a forward reference.  Preparation for
  upgrade to Ember 1.7.0.
Change tests to accommodate pg differences.

Refs #2499
- Since PostgreSQL handles transactions differently than
  MySQL and SQLite3 there are differences in the way and
  number of errors that are returned.  Update tests to
  only check that at least one error of the proper type
  was returned.
Fix markdown/preview tab for mobile

Fixes #3813

- Add togglePreview action to controller
- Implement action and bind attributes
- Remove the now pointless
- Update to comply with issue suggestions
Merge pull request #3834 from rwjblue/update-ember-to-latest

Update Ember to latest stable (1.7.0).
Merge pull request #3836 from jaswilli/ember17-prep

Rework editor save button.
Merge pull request #3830 from wjake/issue-3813

Fix editor markdown tab
Merge pull request #3840 from jaswilli/pg-import-test

Change tests to accommodate pg differences.
Extract starting functionality into an exported class

closes #3789
- Create a GhostServer class to manage state
- index.js now calls start on the exported server
- Alter tests to expect a GhostServer instance