Security release

This is a security release to fix a potential exploit based on Google Site Verification.

It also introduces several new meta tag names.

Add extension.json

Merge pull request #20 from cougrimes/patch-1

Add title markup for OGraph/Twitter

1.2.1: Merge pull request #17 from kghbln/master

1.2.1 release

Compatible with MediaWiki > 1.20

Merge pull request #14 from kghbln/patch-1

Update WikiSEO.php