Fix tag ordering in humanized_essential_tag_string.

* Pick the largest character or copyright tags by post count. Previously
  we picked the tags with the longest names, which was nonsensical.

* Remove tag cateogory logic from config file. We can't avoid hardcoding
  some knowledge about tag categories here, so there's no point in trying.

This affects tab titles on post show pages as well as filenames in
downloaded images.

app/logical/tag_category.rb

@@ -24,11 +24,6 @@ class TagCategory
       @@short_name_mapping ||= Hash[Danbooru.config.full_tag_config_info.map {|k,v| [v["short"],k]}]
     end
 
-    # Returns a hash mapping for humanized_essential_tag_string (models/post.rb)
-    def humanized_mapping
-      @@humanized_mapping ||= Hash[Danbooru.config.full_tag_config_info.map {|k,v| [k,v["humanized"]]}]
-    end
-
     # Returns a hash mapping for split_tag_list_html (presenters/tag_set_presenter.rb)
     def header_mapping
       @@header_mapping ||= Hash[Danbooru.config.full_tag_config_info.map {|k,v| [k,v["header"]]}]
@@ -58,10 +53,6 @@ class TagCategory
       @@short_name_list ||= short_name_mapping.keys
     end
 
-    def humanized_list
-      Danbooru.config.humanized_tag_category_list
-    end
-
     def split_header_list
       Danbooru.config.split_tag_header_list
     end