iTerm2 Nightly supports 24bit color

See: 
- https://code.google.com/p/iterm2/issues/detail?id=218
- https://github.com/gnachman/iTerm2/blob/master/tests/24-bit-color.sh

Let me know if you want me to adjust the way this is designated / worded. I wasn't sure the best way to indicate this in your chart.