Added make_linux_guest.sh script, enabled iwconfig/cfg80211 debugfs in kernel

Adds script make_linux_guest.sh to the image in /root/scripts. The script automatically sets up a linux guest called "linux-guest-1" based on the instructions from http://openmirage.org/wiki/xen-on-cubieboard2.

Wireless extensions (for iwconfig support) and debugfs for cfg80211 are enabled in the kernel config.