feat(authoring): autosave initial authoring
feat(tasks): Creating tasks implemented.

SD-650
feat(users): added userlist service.

SD-650
fix(tasks): Partially fixed small issues, updated to use new api.

SD-650
fix(tasks): Fixed minor issues.
feat(mentions): user mentions basic functionality
feat(mentions): add user info popup
Merge remote-tracking branch 'nikola/auto-save' into devel

Conflicts:
	app/scripts/superdesk-authoring/styles/article-edit.less
Merge remote-tracking branch 'nikola/user-mentions-ui' into devel

Conflicts:
	app/scripts/superdesk-authoring/styles/article-edit.less
feat(notifications): display notification when user is mentioned

when user is mentioned there will be an unread notification in the list

SD-684 SD-656