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.
Currently this is either CLB ID which is an integer or RCv3 LB ID which is a string (UUID). I spoke to @wirehead and we might change this to be only string that will take CLB ID or RCv3 LB ID. It will also take integer for backwards compatibility. Until then you could wait or mention that this takes CLB ID as integer and RC UUID as string.