travis: add extra packages

Signed-off-by: David Scott <dave.scott@citrix.com>
Hook core_test into the build

Signed-off-by: David Scott <dave.scott@citrix.com>
Regenerate OASIS

Signed-off-by: David Scott <dave.scott@citrix.com>
Relicense core_test under ISC, the Mirage standard license

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