[WIP] Slowparse Updates

[flukeout]

We need access to the token for displaying information to the user about their error, but not all of the errors were passing it. This changes that.

@Pomax - does this look sane? Still WIP

[Pomax]

It looks sane, but I would change the order of arguments so that you can rely on the fact that argument 1 is always the error name, and argument 2 is always the token, regardless of whatever other arguments are passed that are not shared by all errors (not all errors ask for this, for instance, so that would change the position of token, sometimes being arguments[1], sometimes arguments[2], you want that to be stable)

[Pomax]

@flukeout what do we want to do with this PR?

[Pomax]

closing, unfortunately.