Update dpm top bar to use agreed branding

- New image and spacing to make it work
- Use logo formatted name without adding line breaks on eo pages

https://www.pivotaltracker.com/story/show/48560501
Custom top bar colours for EO pages

Enable the possibility of having a custom top bar colour. Currently this
is only going to be turned on for the EO offices while we think about
which colours to use for other departments.

https://www.pivotaltracker.com/story/show/48560651
Merge pull request #477 from alphagov/eo-top-bars

EO top bar branding

https://www.pivotaltracker.com/story/show/48560501
https://www.pivotaltracker.com/story/show/48560651
Add virtual tour to number 10 history pages

- Added a virtual tour JavaScript object to load the correct tour
  depending on user selection
- Added the xml manifests for the tours. The acutall assets have all be
  manually put on the correct servers as they are to large for version
  control.
- Included the pano JS using a `javascript_include_tag` on just the
  number 10 page as it seems to large to require for all pages when most
  of them will never need/want it.

https://www.pivotaltracker.com/story/show/47522841
Merge pull request #474 from alphagov/virtual-tour

Add virtual tour to number 10 history pages

https://www.pivotaltracker.com/story/show/47522841