Add a template to create a cirros container.  One great thing about
cirros is that the image you download is 3.5M.

Thanks smoser!

Note by default /etc/inittab doesn't have a /dev/console entry, so you
don't get a login on the lxc-start console.  Adding

console::respawn:/sbin/getty 115200 console

makes that work, but ctrl-c still gets forwarded to init which then
reboots.  So I didn't bother adding console as part of the template
(yet).  Instead I simply lxc-start -d, then lxc-console.
Signed-off-by: Scott Moser <scott.moser@canonical.com>
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>