list复合属性顺序问题

修复list复合属性的语法顺序问题，list-style-image必须放在最后，否则部分浏览器将会解析错误
Merge branch 'master' of https://github.com/doyoe/css-handbook

Conflicts:
	properties/color/opacity.htm
	test.htm
Merge branch 'master' into gh-pages
build