Improve handling of users and roles in admin

Closes #3083 Refs #3229
- Populates the dropdown list in the invite user menu with the
  list of roles a user is permitted to create.
- Users API now checks the invite user request for allowed roles.
- Change API response from 200 to 201 on successful invitation.
- Change API response from 500 to 201 when the user was created but
  the email was not sent.  The client will show a warning notification
  when it sees 'invite-pending' as the new user's status.
- Add support for "?status=all" to the /users endpoint.
- Refactor the route and controller for the /settings/users page so
  that there's only one network API call to load users instead of two.
Signin error notifications kept from stacking

closes #3375
- Prior to showing error notifications, the signin route now calls
  closePassive().
Merge pull request #3388 from jaswilli/issue-3083

Improve handling of users and roles in admin
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
Roles drop down sorted by ID

closes #3391
- Changed sort order to ID instead of name
Merge pull request #3397 from morficus/issue-3392

Removing "full name" auto-popualtion during signup
updated Ember Simple Auth to latest version
Rebind name and password to inputs on signup page

Closes #3410, Ref #3392
- Removed setting name from user email address per issue #3392