mame and rom-tools: Update to 0.148u2 with several change.

* Update mame and its family to 0.148u2
* Let homebrew decide which compiler compiling mame and its family. Note
  that mame's LD is abnormal.
* Remove redefined header path.
* Change rom-tools homepage. As both mame and mess use the same tools
  and mame has a document page related this.
* Fix removed rom-tools target.
* Add ldplayer for rom-tools.

Closes #44.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
xboard 4.7.1

Closes #54.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
nethacked 1.0

Closes #48.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
inform6: add HEAD build, fix overwritten i6 libs

Fixes stable's build process overwriting the inform6 library
files with differently-cased symlinks.

HEAD is not affected, since upstream has fixed this:
https://github.com/DavidGriffith/inform6unix/pull/1

Closes #46.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>
openttd 1.3.0

Upgraded to the latest version of OpenTTD, an open source implementation
of the classic Transport Tycoon Deluxe game.

  * OpenTTD upgraded to version 1.3.0
  * The supporting graphics library, OpenGFX upgraded to version 0.4.6.1

Other than that: Nothing changed from the formular that installed the
1.2.3 version

Closes #45.

Signed-off-by: Misty De Meo <mistydemeo@gmail.com>