Attempt to add travis support based on mirage/mirage-www

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
We need nbd.0.9.1

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #2 from djs55/add-travis

Attempt to add travis support based on mirage/mirage-www