Squashed commit for the two tickets listed

https://github.com/couchbase/couchbase-lite-android/issues/397
https://github.com/couchbase/couchbase-lite-android/issues/398
Fixes 409 Error on PUT checkpoint issue

https://github.com/couchbase/couchbase-lite-java-core/issues/250
Fixes #283 by using a blocking queue

Replace the LinkedHashSet with a blocking queue.

Tests pass on genymotion emulator and nexus 5.

https://github.com/couchbase/couchbase-lite-java-core/issues/283
Change log from error to debug
Merge branch 'feature/issue_249_restart_replications'