Added more 'text modes' to the ATSC Multiple String Structure decoder and convert...

Added more 'text modes' to the ATSC Multiple String Structure decoder and convert text to UTF-8. (Fixes #5162)

 - Added support for decoding ATSC's "Multiple String Structure" text modes 0x1-0x6, 0x9-0x10, 0x20-0x27, 0x30-0x33.
 - Convert decoded text to UTF-8 instead of ISO-8859-1.
 - For unsupported 'compression types' or 'text modes' return a text string "[comptype=0x??,mode=0x??]" indicating
   the attempted compression type and text mode instead of the text segment.

Text output from ATSC's "Multiple String Structure" decoder should properly render in web browsers, specifically Unicode characters >= 0x80.