.pc-only and .mac-only CSS/JS absent in distributed themes

It's fine on yuilibrary.com, but missing when built using yuidoc so you get a few strange UI effects:
![mac_and_pc](https://f.cloud.github.com/assets/370047/2523085/0494c054-b4cc-11e3-8579-0fb0941bf419.png)

Seems to be added by http://yuilibrary.com/combo/js?main.js which obviously isn't included in the yuidoc default theme.