def clear_filter(section, key)
      key = key.kind_of?(Symbol) ? key : key.to_sym
      self.current_filter[section][key] = []
      return nil
    end
def clear_filter(section, key)
      key = key.kind_of?(Symbol) ? key : key.to_sym
      self.current_filter[section][key] = []
      return nil
    end
Clears a single type of filter.
 @param [Symbol]        section  The section of filter to update. :exclude or :include.
 @param [Symbol]        key      The key of filter to update. :actions, :verbs, :names, :controllers.
 @return [Nil]