Add more terminology
Add more terminology

Backfill Queue, Topic, Scan Timestamp, Stable Scan
Initial Build Timestamp

Change-Id: Ia742d6f556ea2b03f1fca7aed19f353af38579d8
Reviewed-on: http://review.couchbase.org/34840
Reviewed-by: Pratap Chakravarthy <3f7aa3c5f732447448ccfcd013fd9591a9825870@couchbase.com>
Reviewed-by: John Liang <c2a3456f8d34e2f912ae00d96ba9294a1f8ee912@couchbase.com>
Reviewed-by: Deepkaran Salooja <94315e58ef7caa1d9829288fe30465d5fa6ccd83@gmail.com>
Tested-by: Deepkaran Salooja <94315e58ef7caa1d9829288fe30465d5fa6ccd83@gmail.com>

jchris/indexing,jchris/indexing,jchris/indexing,jchris/indexing,t3rm1n4l/indexing,t3rm1n4l/indexing