Added support for UIColor

Implemented feature to edit color value with RGB/HSB color pickers.
I'm getting this error here when I try to tap to edit a color
https://gist.github.com/broderboy/ff55ce1b2ecdf9293dea

setup with: 
return FBTweakValue(@"Global", @"Colors", @"Tint", @"#FF4551FF");