Log Message:
Update xmame to 0.84.1.

Changes since 0.83.1:
- Everything from MAME 0.84 (http://x.mame.net/changes-mame.html) and
  MESS 0.84 (http://x.mame.net/changes-mess.html).
- Removed -listinfo, since it's no longer supported by the core.
- The support for network play and rapidfire is no longer in vanilla
  MAME, so they have to be patched into the core for releases.

In addition, network support has been enabled in the package.