Include gray-scale colors as a default theme.

[ColtHands]

Currently gray color theme includes a little bit of tint which is a little bit misleading, but I think a lot of the time one of the most used colors are black-white-gray ones eg (#333333, or #242424, or #ebebeb)

I understand that adding them is trivial, but the same triviality goes for adding those into a default package, so don't see a problem (except for naming) for them being there.

What do you think? Sorry if this post is a dupe, couldn't find similar one...