Added support for CSS

git-svn-id: https://plugins.svn.wordpress.org/pdf-generator/trunk@814762 b8457f37-d9ea-0310-8a92-e5e31aec5664
Changelog

git-svn-id: https://plugins.svn.wordpress.org/pdf-generator/trunk@814767 b8457f37-d9ea-0310-8a92-e5e31aec5664