build: package Mac version of Micropolis

Contributed by benawatt@gmail.com.

Requires App Bundler (https://java.net/projects/appbundler/downloads)
To build, type

ant dist-mac

git-svn-id: http://micropolis.googlecode.com/svn/trunk@877 d9718cc8-9f43-0410-858b-315f434eb58c