Revamp Properties design

[ra4king]

The current Properties design is a mutable and design nightmare. I must have been drunk when I first coded it. Redo it from scratch, but this may break external code.

[ausbin]

To my knowledge, the main external code is the 2110/2220 autograding library, if that's what you mean.

But the code in that library involving Properties is pretty minimal: reading component labels/bitsizes and getting the SUBCIRCUIT property of SubcircuitPeers. (The exception is some semi-complicated code that involves Properties, but that's moreso complicated because both Input Pins and Output Pins are PinPeers, not because of Properties themselves.)

So if you rewrite Properties, just let me know, and I can fix the autograder library fairly easily, basically