Update index.html

Uphaul of the infamous meta field, removed the keywords meta tag because it actually hurts the website's ranks, also added facebook optimizations and a full implementation of twitter cards

The meta field also depends on the site owner's tastes, OG (open graph) should used for sharing on facebook, while twitter cards should be used for sharing on twitter.

Anyone using the template should have full control over the social area of the meta field..

***Schema*** might also be considered in the future to optimize the site to search engines.

Also, valid html5 markup!