core: Add a get_replay method to send a query to a replay endpoint
Add exception handling for server-side error.

Also, add some comments :-)
Add tests for get_replay
Make tail_messages care about seq_id and ask for replay if needed.
Move the replay querying to fedmsg/replay/__init__.py
Add timeout for replay polling
Syntactic fix for SqlStore
Update the tests to take the split into account
Add replay support to the base consumer
Validate replayed messages when tailing.
replay: only append the message if it isn't present in the replay
Add some documentation for the queries
Merge remote-tracking branch 'upstream/develop' into feature/replay-client
Document the 'replay_endpoints' config key
Document the replay_name attribute in the moksha consumer
Avoid the replay codepath in tail_messages if possible
Fix test failures
Use the correct log object here.
Merge branch 'feature/replay-client' into develop