add bootstrap-sass to Gemfile
include bootstrap into css and js files
remove application.css
add navbar to page
add main-page wrapper around page content
add design for region overview
fix regions#index spec to match the updated design
add helper for breadcrumbs and display breadcrumbs on regions#show
display breadcrumbs for rock as well
add some preliminary design for rocks and regions
Merge branch 'bootstrap'

This adds the bootstrap framework, so the design looks a bit nicer. Rocks and
regions views make use of what bootstrop provides now.