Allow users to choose which evaluation keys to log to progress bar

[Valahaar]

Should be pretty easy to implement: we could employ two methods / properties / classmethods for Evaluation, one for a white list of keys to log and the other for a black list, with the white list taking precedence over the black list (so if the user specifies both, we first get the subset of the white list and then remove from them the keys in the black list). By default, everything is logged to pb (as it is now).