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.
Could you mention Nova create server documentation here and saying that: "The payload given here will be passed to Nova create server request when launching server" or something along those lines. This is not important but can be done later if possible.