* update version number in readme.txt
* 2.9.0 changelog
* flesh out changelog + consistent punctuation
* fix changelog prefixes
* remove extraneous .
* testing instructions for 2.9.0
* tweak testing instructions - delete shortcode
* 2.9 version in package-lock
* 2.9 version numbers
* 2.9 release version in package-lock
* Bumping version strings to new version.