Alternate "NES* (nes like)" conversion by 0xDB from
<http://gamedevelopersrefuge.org/viewtopic.php?p=42520#42520>:
> the generator routine is based on PPU descriptions
> http://problemkaputt.de/everynes.htm#ppupalettes and
> http://nesdev.com/2C02%20technical%20reference.TXT and
> on NTSC signal descriptions and on YPBPR to RGB conversions
> improved based on angles of the colorwheel description from
> http://www.ntsc-tv.com/ntsc-index-06.htm