UnifontEX now supports Unicode 15.1

As a result of toying around with something I thought wouldn't work, UnifontEX now supports Unicode 15.1 (for a total of 65422 glyphs). The only casualty was that the IDAT chunks in the TTF2PNG version got grouped. Otherwise, no problems. Go wild with it. UnifontEX can't really go past 15.1 because of multiple technical issues. If you want Unicode 16+, UnifontEX2 will do.