Use govuk_template with new partials for main layout
Adds a build script to update static from govuk_template upstream

- Designed to ensure that static assets and the layout view are coming in from govuk_template upstream
- Refreshes all node modules, then cherry picks from `govuk_template_ejs` into `public`
Sed command for local layout variables
Remove all unnecessary application CSS
Remove `ensure_master` from build.sh

- Can be built from wherever, and shipped to wherever.

Conflicts:
	build.sh
Specify that README instructions are written for local machine
Merge pull request #30 from alphagov/readme-local-machine

Specify that README instructions are written for local machine
Revert "Remove all unnecessary application CSS"

This reverts commit 296e041da661837214b61fbb3618cc459d774e61.
Merge pull request #29 from alphagov/govuk_template

Use the GOV.UK template
Add SASS compilation, replacing static CSS

- Compiled by ./build.sh, but this might be a bit heavy weight (re-installing all node_modules with each CSS build
- Pulls in FET for common helpers
- Basic grid/container layout, enforce max line length
- No styling of page content yet
Apply specific styling required for this service

Doesn't aim to be 100% like the origin, but to have
the same behaviour and rough visual design. As a
distinct service it shouldn't 100% like GOV.UK or
rely havily on it's patterns.

Where possible i've used things from FET and elements
rather than taking from GOV.UK itself.

Roughly replicates GOV.UK styling for:

- Base font size
- Button styling (including transaction style button)
- Addresses
- Info callout
- contact callout (used on drop off)
Document build script use and manual testing

Explains how the build script is used, for setting up the initial application, and
that changes to node_modules and SCSS files will need to be rebuilt and the output
commited.

That isn't ideal, and those files should be treated as generated, built during
setup and/or deploy, rather than commited to the repo itself. Fixing that is
outside the scope of this change, so i'm going to great an issue on the repo
to track that suggestion.

This also adds instructions on manually testin the done/ pages locally, without
having to go through the payment provider. This was extrmely useful while
fixing the application CSS, and I suspect will be useful to someone else in
the future.
Cleanup broken CSS references that were 404ing

These seem to be a holdover from before govuk_template was being used
in a programantic fashion. They're using a different naming convetion
and none of the files referenced would exist.

Also the main application CSS (in assetPath not govukTemplateAssetPath)
was not being served to IE8 or older, which is bad.

In particular the print file was visibly 404ing, as it wasn't obscured
by the IE conditional include.

All of these, save the main application CSS sans-conditional, can be
removed
Merge pull request #32 from alphagov/fix-print-css

Cleanup broken CSS references that were 404ing
Merge pull request #31 from alphagov/fix-application-css

Make application CSS maintainable