You may use/modify my code in pretty much any way you want, with the following restrictions:

1. You may not distribute my original code, or barely modified versions.
2. If you distribute versions with added features (i.e. changed how islands are laid out), you must reference my original plugin.
3. You may not claim you created the plugin, however you can say you modified it to have extra features.
4. You may not gain income from links to either my original plugin, the source code, modified versions, etc.