memoir: Vassar on censorship; Heinlein vs. Serano

The Heinlein tidbit is definitely worth mentioning somewhere (I hadn't
previously blogged it, and if this is where it shows up in my
correspondence history, I guess this is where it shows up in the
memoir and therefore the blog), but I wasn't sure whether it was worth
the wordcount to summarize the whole thread, or if I should gloss it
over with "during a conversation about Milo"—but I'm actually feeling
good about this use of wordcount? It's giving the audience a taste of
who Vassar is (which I can't summarize).