implemented 8 bit color mapped images with 24/32bpp palette.
This is coming from an issue on [[ https://github.com/derf/feh/issues/491 | feh ]] to support indexed TGA images. Written by [[ https://github.com/rofl0r | rofl0r ]], I'm forwarding it because I already have the tools for submission set up.
N.b. I'm not terribly familiar with the particular code style, if there's anything to format differently I'm happy to update.