Create boundOneWay util function

Closes #2958
- Created `boundOneWay` util to extract common pattern of having a oneWay property that doesn't break its binding after being set
- Changed `EditorControllerMixin.willPublish`,  `PostSettingsMenuController.publishedAtValue` and `.slugValue` to use the new `boundOneWay` util
Merge pull request #2960 from novaugust/boundOneWay

Create boundOneWay util function
Allow extra options to be passed to casper tests
Rejigging grunt tasks

- bower only happens in init, not when running the tests as init should
always be run first
Fix trailing slashes output app-wide

closes #2963, closes #2964
- override Ember's `HistoryLocation.formatURL`
- remove overridden `HistoryLocation.setURL`
Merge pull request #2966 from darvelo/trailing-slashes

Fix trailing slashes output app-wide
Update when.js dependency to version 3.2.3
Complete moveover to new Notification API format

fixes #2775
- Fix all occurences of notifications.add to use proper API format
Merge pull request #2970 from halfdan/2775-notification-fix

Complete moveover to new Notification API format
Content screen: Featured posts

fixes #2748
- Properly handle marking post as featured/non-featured
- Show correct notifications
Implements page class toggling.

- Toggles page class when post is marked as static/non-static
Fix slug create and update logic for posts

-Remove unnecessary calls to the slug API endpoint on the
 content screen.
-Only make slug API endpoint calls in editor when the post is new.
-Improve logic for when to update the slug.
Fix csrfSecret handling

Closes #2974
-use req.session.csrfSecret instead of _csrfSecret.
-clear username and password properties from the signin controller.
Merge pull request #2968 from jaswilli/slugs

Fix slug create and update logic for posts
Show notification on successful sign out

Closes #2977
Merge pull request #2979 from jaswilli/issue-2977-signout

Show notification on successful sign out
Lazy load default settings

Closes #2061

- Lazy load the defaultSettings value in Settings model
- Populate individual defaults before read/edit
- Populate all defaults before first browse call
- Remove populateDefaults calls from init code
Fix removeObserver for title property
Merge pull request #2975 from jaswilli/csrf

Fix csrfSecret handling
Merge pull request #2969 from jaswilli/when

Update when.js dependency to version 3.2.3