Remove references to defunct 'OS' module

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Depend on the new 'io-page' library

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

Signed-off-by: David Scott <dave.scott@eu.citrix.com>
Merge pull request #15 from djs55/fixes

Remove 'OS' module, depend on 'io-page' (no -unix or -xen)