MB-12475: Add better error message in cbepctl for timeout errors

A timeout weeror usually occurs when the user enters the wrong
ip address or port number. This changes adds an error message
to tell the user to double check these values.

Change-Id: Ifbfb7f74a1c354720530faede3b86b26fa4592a5
Reviewed-on: http://review.couchbase.org/43148
Reviewed-by: Chiyoung Seo <chiyoung@couchbase.com>
Tested-by: Michael Wiederhold <mike@couchbase.com>
MB-12540: Refactor the way we track snapshot start/end seqnos

For the 3.0 release I needed to add snapshot sequence number
quickly and in doing so implemented an approach that was not
very good and prone to errors. The correct approach is to track
sequence numbers on disk and also to track them for each checkpoint
in the checkpoint manager. This change moves us to the better
approach.

Change-Id: Ifbdd6c87b06767ff8c6504c1058ce11195fa2428
Rollback fix

Change-Id: I2b8ff207832c8a2b944a6c133f30ee2129148966
Fix

Change-Id: I1148a8eb2c64984832b4663f70038711ac727212