Dark theme

[mathiask88]

According to material design specs there is also a dark theme(https://www.google.com/design/spec/style/color.html#color-themes). I think it is important because many people belong to the dark side ;)

[wildhaber]

I will refactor the whole themeing-process anyway so I'll implement the dark theme at this point.

[m-vdv]

+1 for a dark theme! Really awesome project by the way @godesign

[KnoxArg]

+1 Great project!

[goteppo]

+1 - A dark theme would be an awesome addition to the awesome project.

Any update on the timeline?

[Hexodus]

+1 for the dark theme - there're so many light themes but this one is realy exceptional. Please provide this one too. And thanks a lot for sharing with us!