Assert template snippets don't get layout
Fix require line in helper.

Was getting Undefined constant errors in dev randomly.
Remove related items div from error pages

These don't have related items, so this is unnecessary.
Replace section with main tag.

To be consistent with the rest of the site.
Rename :content yield to :wrapper_content

This will avoid conflicting with govuk_template.
Merge pull request #326 from alphagov/add_template_tests

Add some integration tests for the existing templates
Merge pull request #327 from alphagov/various_fixes

Various fixes
Fix indentation in error templates
Inline the 404 report-a-problem form.
Remove unused classes from html element on error pages

Also tidy up the partials.
Switch to use govuk_template for main views.

This commit only deals with the markup changes. CSS/JS changes to follow.
Remove some unused javascripts.
Remove javascript that's duplicated in govuk_template
Replace the myriad cookie functions with the ones in govuk_template