Remove balloon.ml(i)

Part has been moved into domain.ml, part into xen-api.

Signed-off-by: John Else <john.else@citrix.com>
Remove unused parts of netman.ml and add to build

Signed-off-by: John Else <john.else@citrix.com>
Add statdev to the build

Signed-off-by: John Else <john.else@citrix.com>
Import device_common.ml(i) from the xenopsd repo

Signed-off-by: John Else <john.else@citrix.com>