When I first saw this title, I thought it would be a happy-go-lucky tale of two canine friends. Well, spoiler alert: It contains a lot of sadness as well. It’s a new memoir by Martha Teichner, a New York City dweller and a correspondent for CBS’s Sunday Morning, who happens to also be a bull terrier owner and lover. It’s well worth reading if you are a dog person, and I did enjoy it, but there were tears involved…