It may also be better to just punt on lists, and require plugins that need
even lists to encode them. Especially since in many cases, `join(" ", @list)`
-will do.
+will do. Er hmm, if I do that though, I'm actually back to a big global
+%page_data that plugins can just toss data into, arn't I? So maybe that's
+%the right approach after all, hmm.. Except that needing to decode/encode list
+data all the time when using it would quite suck, so no, let's not do that.
Note that for the aggregate plugin to use this, it will need some changes:
* guid data will need to be stored as part of the data for the page
- that was aggregated from that guid
+ that was aggregated from that guid. Except, expired pages don't exit, but
+ still have guid data to store. Hmm.
* All feeds will need to be marked as removable in loadstate, and only
unmarked if seen in preprocess. Then savestate will need to not only
remove any feeds still marked as such, but do the unlinking of pages