add failing test demonstrating CouchDB replication issue

The new test, testRemoteConflictResolution, demonstrates an issue in
replication with CouchDB where conflicts resolved remotely and then
pulled aren't properly reflected on the client.
update ChangeTrackerTest to use the new ChangeTracker constructor

Setting includeConflicts to "false" because that was the old implicit
behaviour.
add test verifying new ChangeTracker constructor param

Confirms that setting includeDocuments to "true" adds "style=all_docs"
to the _changes feed URL.
Add workaroundSyncGatewayRaceCondition() to get around sync gateway issue #271.  Tests now consistently pass against Sync Gateway commit 121c546 and CouchDB 1.3.

https://github.com/couchbase/sync_gateway/issues/271
Update submodule