Add styles to settings dropdown-menu

- added new styles to the dropdown menu
- added icons to menu items
Add styles for headings h1 h2 h3 h4

- added styles for headlines h1, h2, h3, h4
WIP Made a basic sort dialog which is wired up to queries service set sortation.

Once the refactor is done and the wp table is wired directly to the query then hopefully this should update the sortation.
WIP wiring up initial filter values.
Wired up sorting modal to current query sortation.

Not yet updating table when sortation is changed.
Temp solution - moved sortation watcher to wp controller.

Also copied over available columns caching from columns branch.
Always have 3 sort elements in sort selection modal.
Moved modals back into dropdown directive...:>
Reverted Gemfile.lock to that from dev-angular. Must have accidentally committed it.
Merge branch 'dev-angular' into feature/ng-toolbar-sort-by
Fix menu-markup

- cleaned up the action-menu markup
- fixed some issues
Remove former context menu-styles

- removed former context menu-styles
Column headers now displaying first sort element up/down arrow.
Merge branch 'feature/ng-toolbar-sort-by' of github.com:opf/openproject into feature/ng-toolbar-sort-by
Add styles for modal popups

- added styles for modal popups / lightboxes
Merge branch 'dev-angular' into feature/actionmenu-styling

Conflicts:
	app/assets/stylesheets/content/_action_menu_main.sass
Apply new action menu styles to wp context menu
Removed page settings option from toolbar settings.
Merge branch 'dev-angular' of github.com:opf/openproject into dev-angular
Merge pull request #1317 from opf/feature/styleguide-modals

Feature/styleguide modals