Use experimental phpcs rule subset
Make the PHPCS WordPress ruleset directory
Apply PHPCS fixes and some phpDoc improvements
Merge branch 'phpcs-improvements' into widget-customizer

Conflicts:
	bin/.travis.yml
	includes/admin.php
	phpcs.ruleset.xml
Fix .travis.yml syntax error
Add xss ok for phpcs
Use .ci-env.sh (nee .travis.before_script.sh) in pre-commit hook