Unified page class

[cknv]

Now when I think about it, there should probably be a unified way to represent a page, and naturally I am thinking of a class.

Currently my idea is that it must contain two things, a URL and a bytes value, but perhaps it should also be able to hold other data.

It will work very nice as the expected input when writing files, but that leaves the question open to what the loaders should yield. Perhaps also a class, but perhaps not the same.

More thoughts and perhaps prototyping might be needed.