If you checkout the project with svn you can see all libraries in the ./lib directory.
These names of these libs are also in the build.xml.
If you want to package without JGoodies just change the build.xml and rebuild with ant.
This should work:
panel = new JMeldPanel();
panel.SHOW_TOOLBAR_OPTION.disable();
panel.SHOW_TABBEDPANE_OPTION.disable();
panel.openComparison(args[0], args[1]);.
You can use the library in a commercial application.
Please read:
http://www.gnu.org/licenses/lgpl-java.html
See the 'help' in JMeld to see which software/licenses I use.