CBIDXT-97 component wise statistics gathering.

also address CBIDXT-85 to decouple go-jsonpointer from stats.

Change-Id: Ie3ace13896772eca0fa8f743e92c2d59983c9a84
Reviewed-on: http://review.couchbase.org/39305
Reviewed-by: John Liang <johliang00@gmail.com>
Reviewed-by: Pratap Chakravarthy <prataprc@couchbase.com>
Tested-by: Pratap Chakravarthy <prataprc@couchbase.com>