Upgrade rails

Generally a good thing to track.
Merge pull request #188 from alphagov/feature/rails-upgrade

Upgrade rails
Remove gemfury from Gemfile.

We no longer use any gems hosted here.
Bump ruby version to 2.1.4

To keep up to date etc.
Merge pull request #189 from alphagov/remove_gemfury

Remove gemfury from Gemfile.
Merge pull request #190 from alphagov/bump_ruby

Bump ruby version to 2.1.4
Transformation dashboard #version-37

* November 2014 content updates
* Layout fix on homepage
* GOV.UK footer link update

https://github.com/alphagov/transformation-dashboard/compare/version-36...version-37
Service manual updates #version-113

https://github.com/alphagov/government-service-design-manual/compare/version-112...version-113
Merge pull request #192 from alphagov/service-manual-version-113

Service manual updates #version-113
Upgrade therubyracer

Wasn’t compiling on bare machine.

`bundle update therubyracer`
Do the hard work to give more precise error
Merge pull request #193 from alphagov/feature/markdown-location

Do the hard work to give more precise error
Build assets as part of CI job.

This will allow us to catch any errors early.
Bump version of sass.

The older version was causing the following error with ruby 2.1:

```
Mixin "ie-lte" does not accept a content block.
  (in
  /var/govuk/design-principles/app/assets/stylesheets/application-ie6.css.scss)
  /var/govuk/design-principles/app/assets/stylesheets/main.css.scss:1
  /var/govuk/design-principles/app/assets/stylesheets/application.css.scss:8
  /var/govuk/design-principles/app/assets/stylesheets/application-ie6.css.scss:6
```
Merge pull request #194 from alphagov/fix_assets

Bump version of sass.