rebalance, snapshot-marker, getvbmap in projector.

CBIDXT-140: handle Snapshot marker.
CBIDXT-130: handle rebalance
CBIDXT-99:  support GetVBMap in projector's adminport.

- replaced Tracef() messages with Debugf() messages.
- improvised logging for projector feed.
- projector, fixed bugs in repairEndpoints handling.
- refresh bucket for vbmap before making stream request.
- handle snapshot marker.
  * count snapshot marker for stats.
- fixed bugs in endpoint committing harakiri.
- log messages

patchset2:
- amending review comments

patchset3:
- go-formatting.

Change-Id: Iea8397c4c7398a447a77bb5cabbc35ec9040f6d6
Reviewed-on: http://review.couchbase.org/40413
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>