This adds the following status variables:
* wsrep_local_recv_queue_max
* wsrep_local_recv_queue_min
* wsrep_local_send_queue_max
* wsrep_local_send_queue_min

All of these are reset when the status variables are read just like
wsrep_local_recv_queue_avg and wsrep_local_send_queue_avg.
update to lastest 3.x
merge doco from 3.x
Merge pull request #50 from openquery/send_recv_max_min

add local_{send|recv}_queue_{max|min} to status
- so be it!