Prevent mangled POST bodies in http-proxy

This closes #1921. 

`connect-restreamer` is fundamentally nuts and rather fragile. It tries to reserialize the already-parsed body, but it doesn't take into account what format was originally used. Thankfully we can just avoid the issue entirely by putting `http-proxy` ahead of `bodyParser`.

People who have already run the proxy generator probably need to be warned that they won't benefit from this bugfix. (IMO this kind of code really shouldn't be in blueprints in the first place.)