The _QL functions shouldn't require a Thing as their context

Summary: Specifically, Eric is trying to put _QLInput into the Page Header of an unrefied Tag, and it's crapping out because the _QLInput isn't receiving a Thing.

The correct fix for this is that we should be able to pass arbitrary values into _QLInput, and have them fly through the powertrain. That's a good deal of work, though.

This could be fixed a bit more easily by allowing a non-Thing to be passed in, and just eliding the ThingId. But that's a fairly ugly hack, and would require hacking all through the powertrain. Since the immediate problem is easy to work around (by passing an arbitrary Thing into _QLInput), I'd rather not do that.

Older: The implication is that it should be legal to use the _QL functions without a received Thing, probably in the general case.

Are there any more-general ramifications of this?