[indicator-multiload] Ported

Hi, just finished to port it :)

I hope you could review if everything is according to your standards to the repository, but specially the file indicator-multiload/60x11-common_xdg_path.
It comes with xorg package in Ubuntu, but not in the Arch one. So I've copied it, since indicator-multiload needs the environment variable XDG_DATA_DIRS that it sets.

Also I've added the package to the README and fixed it's identation. If you don't like, just let me know :)