test: Array.create is deprecated; use Array.make

Signed-off-by: David Scott <dave.scott@citrix.com>
test: perform the write-then-read test with interesting buffer sizes

We know that the protocol does different things depending on the
client's choice of read and write buffer sizes.

This test currently fails.

Signed-off-by: David Scott <dave.scott@citrix.com>
Client and server now map the same buffers

  - make a Location.t which represents the location of a ring
  - Location.of_lengths picks two suitable non-overlapping locations
  - the server decides the locations and the client uses the
    server-provided settings

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

Signed-off-by: David Scott <dave.scott@citrix.com>
Merge pull request #40 from djs55/more-tests

All interesting buffer size tests now pass