def add_entity section, key, value, enclosure_value = null
      if (tags = self.class.const_get("#{section.upcase}_TAGS"))
        key = key.bowl.to_sym
        tags[key] = value.to_sym
        self.class.const_get("ENCLOSURES_TAGS")[key] = enclosure_value.to_sym if enclosure_value
        self.class.const_get("ENTITIES")[section.to_sym][key] = value.to_sym
        self.class.class_eval %Q{
          alias_method :#{key}, :∀_#{section}
        } # unless self.class.instance_methods(true).include?(key.bowl)
        @shadows = nil
      else
        logger.warn "Trying to add key “#{key}” in an invalid section “#{section}”. Ignoring…"
      end
    end
def add_entity section, key, value, enclosure_value = null
      if (tags = self.class.const_get("#{section.upcase}_TAGS"))
        key = key.bowl.to_sym
        tags[key] = value.to_sym
        self.class.const_get("ENCLOSURES_TAGS")[key] = enclosure_value.to_sym if enclosure_value
        self.class.const_get("ENTITIES")[section.to_sym][key] = value.to_sym
        self.class.class_eval %Q{
          alias_method :#{key}, :∀_#{section}
        } # unless self.class.instance_methods(true).include?(key.bowl)
        @shadows = nil
      else
        logger.warn "Trying to add key “#{key}” in an invalid section “#{section}”. Ignoring…"
      end
    end
Adds new +entity+ in the section specified.
 E. g., call to

     add_spice :linewide, :°, :deg, :degrees

 in HTML implementation adds a support for specifying something like:

     ° 15
     ° 30
     ° 45

 which is to be converted to the following:

     <degrees>
       <deg>15</deg>
       <deg>30</deg>
       <deg>45</deg>
     </degrees>

 @param [Symbol] section the section (it must be one of {Mapping.SPICES}) to add new key to
 @param [Symbol] key the name for the key
 @param [Symbol] value the value
 @param [Symbol] enclosure_value optional value to be added for the key into enclosures section