This PR replaces #145 thereby fixing #126. I've kept the original commits by Tilo for history sake. I also removed the issue @ericf had with using font-weight for active state.
@lkraav and anybody else feel free to review or express concerns. I think its a small amount of CSS for a useful feature.
fyi @sethlivingston @testbird
add button groups
add button groups to manual test page
CLA is valid!
Tested this on all browsers and looked good. Merging.