Update to doclayout-0.3.1.1

0.3.1.1
* Fix the end of the block of zero width characters which contains the
  zero-width joiners and directional markings (Stephen Morgan, #5). This
  fixes a regression introduced in 0.3.1, affecting code points 0x2010 to
  0x2030.

0.3.1
* Improved handling of emojis. Emojis are double-wide, but previously this
  library did not treat them as such. We now have comprehensive support of
  emojis, including variation modifiers and zero-width joiners, verified by
  a test suite. Performance has been confirmed to be no worse for text
  without emojis. (Stephen Morgan, #1). API changes: export
  realLengthNoShortcut, isEmojiModifier, isEmojiVariation, isEmojiJoiner.

(pho)