Time travel: tricky stuff. Meta-fiction: tricky stuff. Combining time travel and meta-fiction? Extremely tricky stuff. Charles Yu’s How to Live Safely in a Science Fictional Universe aims high by doing just this. I read it at a time when I was precisely in the mood for this kind of timey-wimey, universe-bending confusion of a narrative, so that was a point in its favour. And by and large I think Yu manages to pull it off,…