Adding light variant of gruvbox light and improving color mapping! :)

[cal2195]

Made a section of light colors as most of the colors are different.

I'm gonna clean up the color names in the future if they aren't used elsewhere?

[alphapapa]

Hey Cal,

You may want to break with the Solarized-based color organization here, the "baseX" names. Since we have each theme's files in its own directory, you can basically organize the colors however you want. In fact, using a colors.styl file is not strictly necessary, so you could e.g. put the dark-specific and light-specific colors in their own files.

I see that Gruvbox doesn't name them that way, so you don't have to force other themes into that scheme. So you could use the names it uses, like bg, bg0_h, fg, etc. In fact, I would recommend doing this, following the theme's native names and organization as much as possible, which makes it more straightforward to implement the variants.