PC Builder: Part picker

The parts filter is reworked so it's quicker to narrow down a build: sections collapse and expand, the Apply button shows how many parts match, and your active filters appear as removable chips. There are more spec filters too, from processor cache to motherboard networking. The compatibility filter now matches memory to your processor even before you pick a motherboard, and warns you when a processor and RAM use different memory types. We've also fixed several small bugs.