Support 256 color, full 24bit color, and additional ansi reset codes
- 256 color and 24bit color support (#17, #18, #19) - thanks @fetus-hina !
- Add ansi_to_text method (#20) - thanks @fetus-hina !
- reset bg and fg with 39 and 49 codes (#21) - thanks @eXtreme (hat tip @jimbauwens)