ver 3.1.2
* Support extended mouse tracking mode.
  (CSI ? 1006 h and CSI ? 1006 l / CSI ? 1015 h and CSI ? 1015 l)
* Support sixel graphics sequence partially. (DCS .. q .. ST)
  (configure with --enable-sixel option.)
* Support FocusIn/FocusOut event tracking. (CSI ? 1004 h and CSI ? 1004 l)
* Support inputmethod/kbd in win32.
* Add "add_picture", "remove_picture" and "close_pty" commands to
  configuration protocol.
* Add "hide_underline" option.
* Merge SF patches:
  #3524577 (Thanks to Ahmed El-Mahmoudy)
  #3524578 (Install mlterm tools to $(libexecdir)/mlterm instead of $(libexecdir))
  (Thanks to Ahmed El-Mahmoudy)
  patch-ae in NetBSD pkgsrc x11/mlterm.
* Bug fixes:
  Fix a bug which disabled "bd_color" and "ul_color" options in reverse characters.
  (Thanks to Andi Cristian Serbanescu)
  Fix an ibus bug which causes segmentation fault if ibus daemon is not found.
  Fix a bug which could cause failure of opening a new window over ssh connection.
  Fix a bug which causes infinite loop if large OSC sequence is received.
  (Thanks to Koie Hidetaka san)
  Fix a bug which disabled mlconfig and mlterm-menu etc to start if multiple screens opened.