Make Ludicrious available post-install (p2p installation of packages / sharing of files)

[jlkaiser]

Possible to make it so a yum call does peer-to-peer sharing?

example: stack run host command="yum -y install kernel-devel"

[bsanders]

Splitting this off from #187 which is currently being worked on.

Dealing with a limit to the disk usage is still TBD.