Log Message:
Update xmess to 0.77.1.

Changes since 0.74.1 includes:
- Everything from MESS 0.77.
- Ported two more effects from AdvanceMAME: hq2x and lq2x.  (Pieter
  Hulshoff)
- Adjusted and cleaned up some YUV code.  (Alastair Robinson)
- Improved the Superboard II emulation in xmess.  For details, see
  http://claudio.ch/SuperboardII/  (Claudio Nieder)
- The I/O section of the xmess manpage should be more up-to-date.
- A leading '.' on a path now causes xmess to treat it as absolute.
  This allows "xmess.x11 nes -cart ./zelda.zip" to work.
- Set options.mess_printf_output so that xmess spits out more
  informative error messages, e.g., when it's unable to load an image.
- The "-list-dsp-plugins / -ldp" and "-list-mixer-plugins / -lmp"
  commands now cause the program to exit with a return value of 0.