/main_css_action
action to render external stylesheet

Sourcecode in Root/actions.js:
1:   function main_css_action() {
2:      res.dependsOn(res.handlers.layout.modifytime);
3:      res.dependsOn(res.handlers.layout.skins.getSkinSource("Root", "style"));
4:      res.digest();
5:      res.contentType = "text/css";
6:      this.renderSkin("style");
7:      return;
8:   }