Performance: don't send entire request list over IPC

[Mitchell Hentges]

Right now, every time there's a proxy "update", we send the entire list of data over to the renderer process.
Unfortunately, this means that once you hit a couple hundred requests, the time to send the list of requests dwarfs the time between JS ticks, so you get a laggy, unresponsive James.
The solution is to send "deltas" - new requests, and modifying a request with its associated response when it arrives