Fix for udev /run/udev in raring

udev made the transition from using `/dev/.udev` to `/run/udev` for its runtime files - this interferes with Xorg's initial input device scan (which uses `/sys`, and then loads device information from `/run/udev`), but not with devices that are added or removed later (Xorg uses libudev-monitor for those).

I added a symlink from `/dev/.udev` to `/run/udev` that fixes the problem - Xorg can (once again) properly detect all input devices at startup.

This should fix #110.