Remove dependency on 'async_core' in favour of 'async'

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

Signed-off-by: David Scott <dave.scott@citrix.com>
support latest Async APIs

Conflicts:
	async/xen_api_async_unix.ml
Async: open Async.Std as per coding-style

Conflicts:
	async/xen_api_async_unix.ml
Remove dead code

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

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

Signed-off-by: David Scott <dave.scott@citrix.com>
Only test with OCaml 4.01.0 (because conduit + async needs this)

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

Improve async support