Add Bootstrap.
Set Grid system.
System update done.
3 pic version.
Three images ready.
Fix paragraph height issue.
Add links to each buttons. Solve color conflits from Khansite.css
Merge branch 'update_all' of https://github.com/bcipolli/ka-lite into update_all

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Adding the color back in KA-site, because it caused conflicts in subject links color. Use <button> instead of <a> to fix button color issue