On Elle Fanning&rsquo;s birthday this April, someone posted an open letter to the child actress that said, &ldquo;Thank you for being 13 &ndash; and looking it.&rdquo; It praised Elle for her sweet, cute-kid fashion sense, which the letter-writer said steered clear of the &ldquo;over-sexualized world of Hollywood.&rdquo; Well, that was short-lived. On Wednesday, BlackBook posted [...]