clarify license for addon themes

LICENSE

@@ -30,9 +30,13 @@ incorporated into Friendika were provided by their respective authors under
 the LGPL (Lesser GNU Public License) and may result in legal encumberance if 
 you make any code changes to these libraries. 
 
-Addon or "plugin" modules (within the 'addon' directory) are licensed under
-terms provided by the respective software author or authors of those works,
-and MAY include copyleft licenses such as GPLv3, AGPL, and/or commercial
-licenses. For the purposes of licensing, addon modules are considered separate
-standalone works. 
+Addon or "plugin" modules (projects by other authors and fully contained within
+the 'addon' and 'theme' directories) are licensed under terms provided by the
+respective software author or authors of those works, and MAY include copyleft 
+licenses such as GPLv3, AGPL, and/or commercial licenses. For the purposes of
+licensing, addon modules and themes are considered separate standalone works,
+where the "work as a whole" is defined as the embodiment of the theme or 
+addon module.
+  
+