[GREENFOOT-828] Allow inclusion of custom library in exported JAR
Greenfoot allows use of custom JARs, but unlike BlueJ, there's no option to include extra JARs into the exported standalone JAR (made via the Share menu). We should probably add checkboxes like in BlueJ. This may depend somewhat on how we solve GREENFOOT-827 which has a similar issue with how to depend on/include OpenJFX for export under Java 11.
- Issue type: Bug
- Priority: Medium