Initial docs website

Website uses a mixture of React and bootstrap website assets.
Run `grunt build:docs` to generate files
Merge pull request #11 from pieterv/docs-rfc

Docs example [RFC]
Refactor `ProgressBar`
Outputs .progress wrapper if not a child of another `ProgressBar`
Add `striped` and `active` variations
Change `props.text` interpolation to take `%(key)s` for keys:
  min, max, now, percent and bsStyle
No screenreader text by default
Remove  path from readme examples
Add `ProgressBar` example to readme
Fix PanelGroup after upgrade of