This fixes the (mostly theoretical, since we're only parsing data that we write
ourselves) memleak when iif or oif is deserialized multiple times. Unfortunately
it does not fix the memleak when rule is freed, but that'll require a bigger
effort.
Let's just say that the code wasn't fully functional ;(
Since we only had the parser for serialization, and not the writer, we are
free to change the format. So while at it, let's use shorter names in the
serialization format that match the surrounding style.
