RCv3, BfV, purge option, some link fixing, updated rev history

Oy! Writing up two, no three, new features at once, plus discovered some WADL weirdness. Anyway, please take a look. I'll also send out a PDF, which you might find easier to peruse.

Added a concept section for Cloud Bursting with RackConnect V3, added info on using loadBalancer config for RCv3, added info on user_data for BfV, addd purge arg for delete server from scaling group.
"Cloud load balancer" instead of "load balancer". This is needed everywhere since "load balancer" can refer to CLB or RCv3 load balancer.