Offload proxy logic to another library

[jsha]

It looks like the amount of logic dealing with HTTP caching and proxying is relatively small, but it might be worthwhile conceptually to rely on an existing library for it: https://github.com/lox/httpcache.

[rolandshoemaker]

It looks like this library doesn't handle caching from the client side as much as being a intermediate cache/proxy. I'll search around and see if I can find something that would act as more of a client wrapper as that would make some things super easy.

[rolandshoemaker]

I think this may be a good solution https://github.com/gregjones/httpcache.