Added a settings menu item and modal for group by.
Merge branch 'dev-angular' into feature/toolbar-group-by

Conflicts:
	app/assets/javascripts/angular/directives/work_packages/options-dropdown-directive.js
	app/assets/javascripts/angular/models/query.js
	app/views/work_packages/index.html.erb
Added group by item to settings dropdown.
Merge pull request #1318 from opf/feature/toolbar-group-by

Added a settings menu item and modal for group by.