following up with renamed gomemcached Macros.
Updated upr benchmark program in examples/
Implement UprCloseStream API
Add GetPoolServices to Pool.

GetPoolServices implements bucket-independent nodeServices endpoint.
UprCloseStream() and 16-bit opaque.

- fixed example programs.
- upr_bench/bench.go can be used for sanity and raw performance measurement.
Fix for MB-11617
After a rebalance/failover the list of  nodes may not be upto date which
may result in the views code trying to reach a server that may have been
removed. The fix for this is to refresh the bucket and retry the view
atleast once before giving  up.
Remove lock from ForwardUprEvent
Fix crash on close with multiple upr connections