Add test for basic case of saving a remote checkpoint when remote side does not throw an error (issue #108)

https://github.com/couchbase/couchbase-lite-android/issues/108#issuecomment-29043658
Had to comment out setting db to null to make test pass that was checked in in last commit (issue #108)

https://github.com/couchbase/couchbase-lite-android/issues/108#issuecomment-29043658