Bumping version to 0.9.2

Changes here - https://github.com/alphagov/govuk_template/pull/100
Can we add the other features added since 0.9.1?

- Set page background to match footer background 64403bab02bed985f74c54f6dd5fc38e866a7a25
- Add HTML5 display definition 038ae22dd638714bef22fd1e58379a7e452906ce