Ironed out issues with generating an application bundle with universal
binaries on supported systems. Fall back to bundling a single
architecture when support for universal binary generation is not
available. Tested on Mac OS X 10.5.8 (and 10.5 SDK).
https://bugzilla.icculus.org/show_bug.cgi?id=5986
Created make-macosx-app.sh to handle manually creating an app bundle from other scripts.
Updated make-macosx.sh to create bundle with make-macosx-app.sh (TODO: make-macosx-ub.sh support).
Updated Makefile to create bundle with make-macosx-app.sh and zip up the resulting ioquake3.app if ARCHIVE is defined.