[Libguestfs] [PATCH FOR DISCUSSION ONLY] Rewrite libguestfs-supermin-helper in C.

This needs loads more testing before we include it. However it's in good shape for testing and review. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-df lists disk usage of guests without needing to install any software inside the virtual machine. Supports Linux and Windows. http://et.redhat.com/~rjones/virt-df/