stringr 1.3.1

• str_replace_all() with a named vector now respects modifier functions (#207)

• str_trunc() is once again vectorised correctly (#203, @austin3dickey).

• str_view() handles NA values more gracefully (#217). I've also
  tweaked the sizing policy so hopefully it should work better in notebooks,
  while preserving the existing behaviour in knit documents (#232).