Allow for UTF-8 byte order mark in input files.

    # have surprising results.  So in here we read in all files in UTF-8

    # (the default) or in some other encoding specified through --encoding

    # option and convert it to UTF-8 internally.

    #

    # We also allow for UTF-8 byte order mark.

    class IO

      @@encoding = "UTF-8"

      @@encoding = "BOM|UTF-8"

      # Sets the external encoding to be used for reading files.

      # When it's different from UTF-8, the input will be converted to UTF-8.

      def self.encoding=(e)

        if e =~ /^UTF-8$/i

        if e =~ /^(BOM\|)?UTF-8$/i

          @@encoding = e

        else

          @@encoding = e+":UTF-8"