ZDBSP 1.18.1: Minor bugfix release

[randi]

ZDBSP has received a small bug fix and is now at version 1.18.1. This corrects a problem in earlier versions that could potentially create invalid nodes with maps that have more than 65535 lines or with maps that use the new node format introduced in ZDBSP 1.18.

[Hirogen2]

The release does not run on sparc64-linux. __BIG_ENDIAN__ is not set, and so the program aborts at runtime when attempting to read the WAD directory and does not swap the numbers. The following patch resolves this for me.