CssUrlRewrite Filter
Preprocess Css files and rewrite Url to correctly resolve url() and @import directive

Signed-off-by: Marco Sbragi <m.sbragi@gmail.com>
Modified output to show filename before minified code
Useful to check the list of minified files when inspecting the resulting file during development

Signed-off-by: Marco Sbragi <m.sbragi@gmail.com>