Currently, our source code is organized mostly in a few large modules, and even some of the smaller modules are combined within larger files. At this point, it makes sense to split things up somewhat.

@kupiakos has a proposal for this in f5c5193.

If you're going to take a stab at this, please comment first so that I can suggest a module breakdown to start with. We'll want to start with something very coarse-grained so that it's obviously the right move, and then we can get more fine-grained over time if we decide it's worth it.