Make SVG icons scalable
Import missing mixins in membership Sass file
Merge branch 'master' of github.com:guardian/frontend into scale-svg-icons
Use rem mixin in sprite files
Merge branch 'master' of github.com:guardian/frontend into scale-svg-icons

Conflicts:
	common/app/assets/stylesheets/module/content/_media.global.scss
Merge pull request #5256 from guardian/scale-svg-icons

Make SVG icons scalable on root text resize