stringr 1.1.0

• Add sample datasets: fruit, words and sentences.
• fixed(), regex(), and coll() now throw an error if you use them with
  anything other than a plain string (#60). I've clarified that the replacement
  for perl() is regex() not regexp() (#61). boundary() has improved
  defaults when splitting on non-word boundaries (#58, @lmullen).
• str_detect() now can detect boundaries (by checking for a str_count() > 0)
  (#120). str_subset() works similarly.
• str_extract() and str_extract_all() now work with boundary(). This is
  particularly useful if you want to extract logical constructs like words
  or sentences. str_extract_all() respects the simplify argument
  when used with fixed() matches.
• str_subset() now respects custom options for fixed() patterns
  (#79, @gagolews).
• str_replace() and str_replace_all() now behave correctly when a
  replacement string contains $s, \\\\1, etc. (#83, #99).
• str_split() gains a simplify argument to match str_extract_all()
  etc.
• str_view() and str_view_all() create HTML widgets that display regular
  expression matches (#96).
• word() returns NA for indexes greater than number of words (#112).