Add option to redirect rather than proxy to http destinations

[jsdw]

Currently, weave proxies everything, so you think you're talking to localhost:1234 but you're actually talking to foo.com.

An option could be added to tell a route to send back redirect headers rather than internally proxy the request.

Weave could then be used to forward you from some url you've constructed to the real deatinstion(s).

Is this actually useful though?

[jsdw]

Possibly a more useful feature down the same line is having weave handle redirects itself rather than giving them back to the user.