Updated location of RFC reference XML files
Renamed KSK "Double-Signature" rollover to "Double-KSK"

As agreed at the teleconference between the authors on 10 June 2014.
Remove rollover summary table

As agreed at the teleconference between the authors on 10 June 2014.
The summary table only listed the order the different records were
published and did not really contribute to the understanding of the
document.