Add feature and update site for darker theme

Your darker theme is fantastic!

I've setup the feature and update site for your darker theme to make it easier to distribute.

In addition, I created a gh-pages branch that can be used to host the updatesite.

You'll want to replace my github account with yours in feature.xml and site.xml.

Additionally, I can walk you through the setup of a github page (gh-pages branch) to host it on your own gh if you'ld like.

(One other note, I didn't see a license on your work so I used the default eclipse license. You might want to change that as well if it's not suitable).