Fix double-loading of Tag::Tag class in Ruby 1.8.

    # Loads tag classes from given dir or single file.

    def load(path)

      if File.directory?(path)

        Dir[path+"/**/*.rb"].each {|file| require(file) }

        Dir[path+"/**/*.rb"].each do |file|

          # Ruby 1.8 doesn't understand that "jsduck/tag/tag" and

          # "./lib/jsduck/tag/tag.rb" refer to the same file.  So

          # explicitly avoid loading this file (as it's required on

          # top already) to prevent warnings of constants getting

          # defined multiple times.

          require(file) unless file =~ /jsduck\/tag\/tag\.rb$/

        end

      else

        require(path)

      end