Remove compass, compass-rails dependencies

Since 62885244 we rely on only one CSS mixin library: Bourbon.

User Story # 11315

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Bump livingstyleguide to 1.2.0.pre.1

This release series no longer depends on Compass.

Signed-off-by: Alex Coles <alex@alexbcoles.com>
Merge pull request #1794 from opf/feature/remove-compass-framework