Don't let filenames be changed to Windows' backslash-notation.

node/utils/Minify.js

@@ -57,6 +57,7 @@ exports.minify = function(req, res, next)
   filename = path.normalize(path.join(ROOT_DIR, filename));
   if (filename.indexOf(ROOT_DIR) == 0) {
     filename = filename.slice(ROOT_DIR.length);
+    filename = filename.replace(/\\/g, '/'); // Windows (safe generally?)
   } else {
     res.writeHead(404, {});
     res.end();