Fix Invitations

no issue
- added `invited-pending` when resending invitation
- promise chain was missing a return statement
- email error was masked and front end showed success notification
Fix lazy loading of settings

Closes #3281

- Add the missing return to populateDefault
- Wrap defaultSetting in [] when passing to readSettingsResult
- Populate default value of dbHash in parseDefaultSettings
- Modify migrations.init to only load databaseVersion for export_spec test
- Fix spacing in test util file and null reference error in test
- Uncomment user tests (but add .skip) and remove settings from testUtils.setup()
Adding new {{title}} helper

closes #3389
Fixup signin and signout

No Issue
- Move authentication related handlers to the Application route.
- Switch Sign Out from a button to a link.  Use the signout route
  to handle invalidating the session and redirecting instead of
  an action from a button.
- Clear error messages on signin page when pressing log in button.
- Errors are now always shown on sign in screen and a success
  notification is shown after sign out.
- Update functional tests.
Ghost instance not needed in update check test

Refs #3424, Refs #3444
- API and test suite refactoring triggered a conflict with
  the way update_check_spec.js was written.  Using a running
  copy of Ghost is no longer needed in those tests so it
  was removed.
Merge pull request #3445 from ErisDS/issue-3389

Adding new {{title}} helper
Settings screens redirect for certain roles

Closes #3291
- Adds redirects based on roles as defined in the case
- Adds new mixin `CurrentUserSettings`
- For authors, all settings pages redirect to `users/self`
- For editors, all settings pages other than specific users redirect to `users`. Any user that is not self or an author redirects to `users`
Merge pull request #3424 from jgable/fixSettings

Fix lazy loading of settings
Merge pull request #3444 from sebgie/fix-invitations

Fix Invitations
Merge pull request #3448 from jaswilli/update-check-test

Ghost instance not needed in update check test
Uncommenting fixed tests
Merge pull request #3447 from jaswilli/auth

Fixup signin and signout
Merge pull request #3416 from alarobric/case_3291

Settings screens redirect for certain roles
Add User Role Dropdown

Closes #3402, Closes #3428

------------------

 ### Components
- Added GhostSelectComponent to handle async select creation (h/t @rwjblue)
- Added GhostRolesSelector (extends GhostSelect) for displaying user role options
- Created StoreInjector for surgically inserting the store into things that normally wouldn't have them.

 ### Users Settings
- InviteNewUserModal now uses GhostRolesSelector & defaults to Author
- The role dropdown for user settings has permissions set per 3402

 ### User Model
- Added `role` property as an interface to getting and setting `roles`
- Refactored anything that set `roles` to set `role`
- isAdmin, isAuthor, isOwner and isEditor are all keyed off of `role` now

 ### Tests
- Added functional tests for Settings.Users
- updated settings.users and settings.users.user screens
- fix spacing on screens

 ### Server Fixtures
- Fixed owner fixture's roles