add "Living Styleguide"

- convert old static styleguide to HAML
- build fully dynamic, "living" styleguide, make resourcefull-ish
- add basic spec test, trying out screenshots
- doc: add some research links, ideas
- disable some js for merging
- move logo image to proper place
- styleguide: fix images (assets paths) and links (#foo)
- fix spec/spec_helper_feature.rb