(#136) - Cloudant fix for "Testing all docs"

In Cloudant / Big Couch, the _changes feed is composed from
multiple shards and there is no guarantee that ordering
will be consistent between multiple calls.

The fix is just to test that the changes feed includes the entries
we require regardless of the order.
(#136) - Cloudant fix for "Testing deleting in changes"

Given that we cannot assume the order of a changes feed on Cloudant / Big Couch,
test that the change is included in the _changes feed following the initial
database sequence number.
(#136) - Cloudant fix for "Testing include docs"

The ordering of the changes feed is non-deterministic so just test that
the expected entry is present.
(#136) - Skip "Testing conflicts" in _changes

Cloudant doesn't currently support conflicts=true on the _changes feed.
Skipping this test for now until I find out more about why/whether it
will be supported.
(#136) - Cloudant fixes for attachment tests

We cannot rely on an ordered update sequence in Cloudant.
Instead, request the _changes feed following the initial docment update
using the "since" parameter. There is still potential for this to fail
because _changes may return entries before that specified by "since" -
the guarantee is that all entries following "since" will be returned.

Possibly one to review if we find that the test fails occasionally
(for me it is stable).