API is not super convenient and implementation is lousy, but uploading
files is not a super common operation so that should be fine.
At least it supports large files with only a single in-memory copy.
And with this, I have a working rewrite of the manned.org backend into
FU. \o/
The $st->row methods are very useful even for queries that may not
return anything, so their old behavior was unhelpful. Interestingly
enough, the error-on-multiple-rows did catch an actual bug in
Manned.org, so I'm keeping that behavior.
