css-validator downloaded from jigsaw.w3.org
http://jigsaw.w3.org/css-validator/DOWNLOAD.html

Looks like the above is not being updated, but the w3c github page is:
https://github.com/w3c/css-validator

W3C Software license (http://www.w3.org/Consortium/Legal/2002/copyright-software-20021231)

To execute via command-line:
# cd ant_build.js\lib\cssValidator
# java -jar css-validator.jar ...

To get it to dump help, throw a bad argument:
# java -jar css-validator.jar --help
