xendevsummit14: add placeholder including graph

Signed-off-by: David Scott <dave.scott@citrix.com>
xendevsummit14: more slides

Signed-off-by: David Scott <dave.scott@citrix.com>
xendevsummit14: polish the xenstore section a bit

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #22 from djs55/xendevsummit14

First chunk of xendevsummit14 slides