Document meaning of some of the less obvious terms of the protos.

[Tilps]

Specifically at least the 'value' in the chunk data format. (If we want to use it for resign analysis it has to be the value resign is predicated on, which is the value of the best move (ignoring temperature). But root Q is something some people have expressed an interest in.)

[Error323]

I indeed intended it to be the value that resign is predicated on. I guess in terms of documentation, this should be comments in the proto files?

[Tilps]

Yeah I like proto file comments.

[dubslow]

I don't understand what value-to-us root q has, since it's up to that player at that time what move to play. We only use averaging over all moves as a probabilistic estimation of what some unknown future opponent might play, as opposed to when it the player's turn right now, there's total certainty about which move will be played (putatively speaking). It should just be the best move value, which is what we currently use for resign. (IOW, agreed with both of you.)