Use slimmer for standard GOV.UK template

Change the nokogiri version down due to a conflict with the version that
slimmer wanted.
Add IE specific stylesheets, add them to precompile
Add govuk frontend toolkit
Use asset group in development
Add basic styling for dummy content

Style the header and all the bits inside it as per the latest designs.

- Set an empty `global-breadcrumb` so that the breadcrumbs from slimmer
  are removed
- Use a main around all the content on the app
- Add reset to remove browser padding/margin and other defaults
Add styles for govspeak content and nav

Steal the govspeak styling from whitehall for the moment. It will
probably want interating later.
Add and style document footer
Add slimmer header_footer_only
Add email/feeds image sprite
Add updates and summary. Fix gutters.
Fix config for css in asset pipeline
Use slimmer for standard GOV.UK template

Change the nokogiri version down due to a conflict with the version that
slimmer wanted.
Add IE specific stylesheets, add them to precompile
Add govuk frontend toolkit
Use asset group in development
Add basic styling for dummy content

Style the header and all the bits inside it as per the latest designs.

- Set an empty `global-breadcrumb` so that the breadcrumbs from slimmer
  are removed
- Use a main around all the content on the app
- Add reset to remove browser padding/margin and other defaults
Add styles for govspeak content and nav

Steal the govspeak styling from whitehall for the moment. It will
probably want interating later.
Add and style document footer
Add slimmer header_footer_only
Add email/feeds image sprite