JIRA: https://jira.spring.io/browse/INT-3325
JIRA: https://jira.spring.io/browse/INT-1870
Optimized MGS for QueueChannel - uses a LIST for
each channel and LPUSH, RPOP.
* Also fix MutableMessage to be Serializable
INT-1870 Priority Redis Channel Message Store
Supports priorities 0-9 (+ no priority).
Priorities out of that range are treated as no priority.
Polishing - Add Marker Interfaces
* Emit a `WARN` log if a channel is used with a regular MessageGroupStore
* Allow message-store on namespace when defining a priority channel
INT-3325 Polishing; PR Comments
Fix some typos in JavaDocs and Docs
a8c8a4fed5