Add category_sets to piece
Add mobile preview link to doc detail page
Hide initial category_set into piece
Remove unused brackets
Now use unique sort key to sort marker by category

Conflicts:

	app/models/map/content/marker.rb
Sort category_sets
Add gp_article_content_docs to piece setting
Add docs_order to piece setting
Add doc_style to piece setting
Add new settings to show page
Add more link to piece setting
Merge branch 'master' of github.com:zomeki/zomeki-development into revise-gp_category-docs-piece
Merge branch 'revise-gp_category-docs-piece' of github.com:zomeki/zomeki-development into revise-gp_category-docs-piece
Change date_style to local
Use doc_style instead of list_style
Add brackets to asc/desc
Apply docs_order to public side
Apply new piece settings to public side
Now accept in case of no categories (only category_type)
Just shoten code