marks checker reads whole file first, doesn't need to

[Fred T. Hamster]

marks checker and others inefficient

these guys seem to read all the links at once.

the checker shouldn't do that though; it should just be able to stream the links as it sees them.

ahhh, perhaps this is because we have this notion of a category tree, and we don't actually know what will get added to the tree ahead of time, from later in the database file.
ugh. but still, for the marks checker, we can kind of assume it was canonicalized already?
or we can explicitly state that it should have been.

if we keep the current output style, which is just the bad links, we can stream in the marks checker and not build the whole tree thing.