Pause Render Button

[lukesleftleg]

I realise that the team are all hard at work on far more exciting stuff, but I'd like to make a low-priority quality-of-life feature request.

A Pause button would be really handy actually. For when you've a really long render, and OpenCL has all but locked up your machine, and you just want to take a quick look at some very important JPGs of cats saying stupid stuff, without losing all the render progress you've made so far.

Just for far in the future, when there's only bells and whistles left to be added.