Issue #25 - extend the allowed time for this test to run

Previously this test was executing very quickly, because it was essentially processing everything at once, which is exactly the core issue of issue #25.

By expecting the test to complete so quickly, we are advocating mis-behavior.  Change this to expect the batcher to stream things out more over time, and therefore allow more time for the test to complete.

https://github.com/couchbase/couchbase-lite-java/issues/25
Issue #25 - add two tests which verify that latency was not adversely affected.

https://github.com/couchbase/couchbase-lite-java/issues/25