Change signout link to button

References https://github.com/TryGhost/Ghost-UI/issues/65

- Swap signout link from an `<a>` tag to `<button>`
- Changed tests to match new element
Redirect authors and editors away from debug page

A signed in user with role author or editor will be redirected back to
/ghost.

closes #3292
Show error notifications on "reset password" page

closes #3330
- Caught errors are displayed using notifications util
Signin error notifications kept from stacking

closes #3375
- Prior to showing error notifications, the signin route now calls
  closePassive().
Signin: Proper notification if user not found

closes #3374
- If user object is returned but undefined, we'll display a
human-readable
error notification (user model)
- If user object is returned, but the user is inactive or invited (but
not
activated), we'll display a human-readable error notification
Five posts per page
Merge pull request #3354 from JohnONolan/ppp
Merge pull request #3368 from felixrieseberg/master

Show errors on reset page (Closes #3330)
Merge pull request #3376 from felixrieseberg/iss3292

Redirect authors and editors away from debug page
Merge pull request #3377 from PaulAdamDavis/signout-button

Change signout link to button
Hides <Users button for authors

closes #3295
- The <Users button visibility is now restricted by user role
Fixing resend user invitation

closes #3396
- passing role when resending a users invitation
Removing "full name" auto-popualtion during signup

closes #3392
- removing data-binding attribute for "name" input box on signup screen
- removing data-binding attribute for "password" input box on signup screen
- making "email" the first input box and "name" the 2nd
- removing "autofocus" attribute for "email" input box on signup screen
Merge pull request #3385 from felixrieseberg/iss3375

Signin error notifications kept from stacking
Merge pull request #3386 from felixrieseberg/iss3374

Signin: Proper notification if user not found
Merge pull request #3394 from IanMitchell/settings-user-button

Hides <Users button for authors
Merge pull request #3398 from morficus/issue-3396

Fixing resend user invitation
Merge pull request #3397 from morficus/issue-3392

Removing "full name" auto-popualtion during signup
Implement user and related content deletion

Closes #3100

* Introduces `destroyByAuhor`, given a context and an id, it will check if context has permission to delete the user by the id, and then deletes all the content where `author_id` is id, and then deletes the user
* Does multiple checks to make sure user exists

Caveats / questions

* I've added a `.get` route as well for testing. I'll remove that if I get thumbs up from yall
* Not sure what the return value should be on successfull deletion. Currently it's `{user: []}`
* Not sure what to do with a process that might fail halfway through. Deleted all the content, but user remained because of an error.