4.3.0 Rewrite of comments system frontend

• New tagging system for comments.
• Users without avatars now get auto-generated identicons.
• Ability to define custom paths for guides.
• Allow @links to private members.
• Allow @cfg with subproperties inside class-level doc-comment.
• Sort mixins/requires/uses lists in export.
• Constructors are now always public, unless explicitly marked with @private
• Skip the "this enum is for documentation only" warning for normal enums.