Make images stay in a row for tablets
Update index.html

Add col-xs-12 class for images. Reason: they are still displayed like 1 image in a row for tablets, despite col-sm-4 class
Add <picture> for the main banner on top: now should show cropped image on iphone
Merge branch 'master' of https://github.com/korneevaed/mockup_to_website
Resolving merge conflict