Increment version to v2.2.1
Increment version to v2.2.1

* Follow up to commit 5cb7499 of 2015-08-19 so that this extension
  now shows up nicely on special page "Version"
* Rename this extension consistently to Semantic Rating like for
  most other major semantic extensions and to sync with documentation

Change-Id: Ica4f6f6fbc6386d53affe46df3a1ae5809f8cfa6

wikimedia/mediawiki-extensions-SemanticRating,wikimedia/mediawiki-extensions-SemanticRating