UprFeed is implemented as a genServer routine.

- race-condition: sending on a closed channel (output channel).
- race-condition: async access over connPools.
- UprFeed opens a connection with all kvnodes, application like projector
  will be co-located and will connect with local-node.
  - projector does not need connection retry.
  - bug-fix: to close gomemcached connection after GetFailoverLogs() call.
  - using sync.WaitGroup{} to synchronize feed closing.
- fixed example scripts.

Change-Id: I7e4521373f224c285f7e6ebd7e4578812a5fc7f8