fix/457: css fix for featured walkthroughs

The two featured WT iframe will show below each other in small screens
Merge branch 'master' into feature/455-new-frontpage-top

Conflicts:
	sites/all/modules/features/walkthrough_global/walkthrough_global.install
Merge pull request #52 from csanyiarpad/feature/455-new-frontpage-top

fix/457: css fix for featured walkthroughs