async example: don't forget to (i) perform RPCs; and (ii) exit afterwards

Two critical bugs in an RPC-testing program fixed.

Signed-off-by: David Scott <dave.scott@citrix.com>
Add some more OASIS cruft

Signed-off-by: David Scott <dave.scott@citrix.com>
test: add Async -> Lwt RPC test

Signed-off-by: David Scott <dave.scott@citrix.com>
async: add a server example

Signed-off-by: David Scott <dave.scott@citrix.com>
test: add an Async -> Async example

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

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

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

Signed-off-by: David Scott <dave.scott@citrix.com>
Update license from FreeBSD to ISC

This is in sync with Mirage, whose code we 'include' (Cohttp's IO
modules)

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