Embed version & multiple tabs

[sergiocruz]

I added support to pass a new prop called version. This prop is set to 2 by default.

I also made it so that the tab prop can now accept two tabs separated by a comma, for example:

• js,result
• css,js
• html,result
• ... etc

Please let me know if there is anything else you would like me to address before merging :)

By the way this PR addresses issue #1