Handle toggleing the content screen on mobile.

Closes #3520.

Move the custom jQuery animation into an action on the controller so
that we can trigger it from within the route if needed.
Refactor notifications to prevent stacking.

Closes #3511, Closes #3512, Closes #3526
- show* methods now close existing passive notifications by
  default.  They also now take an optional options object where
  existing parameters such as "delayed" and "defaultErrorText"
  can be passed in as well as the new "doNotClosePassive" flag.
- Removed all explicit calls to notifications.closePassive except
  for the few places where it makes sense to call it separately.
Admin isn't shown "make owner" option

closes #3558
- Replaced canAssignRoles as "show user" conditional with new
"canMakeOwner"
Descriptive error if user by mail not found.

closes #3537
- Replaced generic NotFound error with descriptive NotFoundError.
Merge pull request #3561 from felixrieseberg/iss3558

Admin isn't shown "make owner" option
Merge pull request #3521 from jaswilli/notifications

Prevent stacking of notifications
Merge pull request #3560 from felixrieseberg/iss3537

Descriptive error if user by mail not found.
Update Ghost-UI with grunt init

Closes #3554

- Adds a shell command to update Ghost-UI
Show "Make Owner" only if displayed user is admin

closes #3570
- Added ‘controller.user.isAdmin’ as an condition for displaying the
“make owner” option
Ensure keyboard navigation matches custom post sorting.
Small performance tweak for Posts ordering.

* Move publishedAtCompare to standalone function in closure scope
  (allows better browser optimizations).
* Avoid getting the same field (published_at) more than once.
Error modifying "author" attribute before post record has been created

fixes #3523
- when changing the author, added a check to NOT trigger a save if the post has not been created/saved as yet
fix most recent post stolen by the last logged in user AND only show active users in post-settings-menu drop-down

fixes #3549 fixes #3528
- instead of grabbing and setting the author after fetching the list of users, get the author info from the models "author" property and set it when that value returns. (3549)
- added filter to the PSM's "authors" attribute to only display active users (3528)
Stop event propagation when hitting "enter" in the gh-blur-input component

fixes #3516
- new behavior is disabled by default
- added new stopEnterKeyDownPropagation property enable new behavior
Replacing "touch start" with "tap" event, provided by hammer.js

fixes #3502
Insert inline code shortcut for editor

closes #3543
- Wired up existing code shortcut in codemirror-shortcuts.js in
editor-shortcuts.js
Merge pull request #3562 from PaulAdamDavis/3554-update-gui

Update Ghost-UI with grunt init
Merge pull request #3572 from rwjblue/fix-keyboard-nav-for-posts

Ensure keyboard navigation matches custom post sorting.
Merge pull request #3574 from rwjblue/speed-up-posts-orderby

Small performance tweak for Posts ordering.
Autofocus on input fields after routing

closes #3538, closes #3541
- The “autofocus” property isn’t considered by browsers if the element
is created after the page has been loaded. The Ember cookbook
recommends extending the input type with a manually triggered
autofocus, which I included here.
- This introduces the new helper “gh-focus-input”, an input field
gaining focus even when routing occurs.