Make it robust against failures when trying to add cookies to global store.  Log an error but don't break the overall behavior.
1. Create a test which reproduces at least some of the behavior observed in issue #108.

2. re-enable testPusher(), it was apparently not running before because of the signature
3. light refactoring to re-use some code.
4. Introduce a mock replicator
make some fixes to the test
make mock replicator a little more realistic by adding a small delay.
Fix for problem where it was saving the checkpoint for a remote immediately rather than waiting for the PUT to _local to finish.  See issue #108

https://github.com/couchbase/couchbase-lite-android/issues/108#issuecomment-28858186