Update mlterm to 3.1.8.

Changes per doc/en/ReleaseNote:

ver 3.1.8
* Support framebuffer on FreeBSD. (Experimental)
* 'key' configuration file accepts Button1 - Button5.
* Remove "conf_menu_path_1", "conf_menu_path_2", "conf_menu_path_3" and
  "button3_behavior" options which are integrated to shortcuts.
  [Migration]
  (~/.mlterm/main)        (~/.mlterm/key)
  conf_menu_path_1=... => Control+Button1="menu:..."
  conf_menu_path_2=... => Control+Button2="menu:..."
  conf_menu_path_2=... => Control+Button3="menu:..."
  button3_behavior=... => Button3="exesel:..."
* Add "set_shortcut" command to configuration protocol.
* Bug fixes:
  Fix the bug of DECCRA.
  Fix the bug which broke input string of "ExecCmd" field of the connection dialog in win32.
  Fix the bug which didn't redraw a part of full-width characters when window is exposed.
  Enable to change "vertical_mode" option dynamically in framebuffer.
Updated x11/mlterm to 3.1.8
Update onscripter to 20130223.

Upstream changes summary (only Japanese log available)

20130223
 - fix bug of game insn that resets loaded default cursor
 - fix bug that backlog doesn't show all text due to buffer overflow
   in some case

20130216
 - implement luacall reset
 - fix bug in definereset insn that resets global variables even during
   globalon insn is active
 - make definereset insn load system.lua
 - handle >255 values for sprite transparent value

20130203
 - fix iOS SDK bug

20130202
 - implement checkkey insn
 - implement NL_dofile, NSGetSkip, NSGetWindowSize, NSTimer, NSGetKey,
   NSUpdate, NSSpClear, NSSpGetInfo, NSSpGetPos, NSSpLoad, NSSpMove,
   and NSSpVisible insns for NSLua
 - update Android SDK
Updated games/onscripter to 20130223
Update to 4.39.1. From the changelog:

- fix a bug that could crop up when retrieving mail via IMAP from
  Gmail, and the Gmail servers provided weird data in their header
  extensions. Thanks: Krzysztof Warzecha.
Updated mail/getmail to 4.39.1
Check nspr version in pkgsrc side.
xulrunner-19.0.3 needs 4.9.4 of nspr or later. Fix build.
- Ignore dictionary entries which cause skkserv not to start.
  Diff is taken from FreeBSD ports.
- Combine patch-af and patch-bsearch into single file, because those are
  diff files for the same file.
- Add LICENSE.
+ ImageMagick-6.8.3.9, atari800-3.0.0, dar-2.4.10, pngcrush-1.7.53,
  py-httplib2-0.8, py-trueskill-0.3.1, py-virtualenv-1.9.1,
  wdiff-1.2.1, xosview-1.13.