Add color cycling as image post-process

v1.594

[New] Major update: Color cycling       -cycle : palette cycle using defined palette       you can use more than 4 colors to cycle,
      for example: -cycle -pc1,2,3,4,5,6,7,8,9,10
      -revcycle : palette cycle in reverse order

[+++] "Super random"
      -reroll : When the "multiple images" flag is set (-repeatNN)       along with a random palette (-pr), set new random colors every frame.       for example: -repeat10 -pr -reroll
      (This uses GIF local color palette)