new permissions:

* list members may be nominated as moderators by admin
* admin may allow moderators to nominate more moderators
* admin may set allowed senders to one of the following:
    * owners and mods
    * all subscribers
    * everyone
* moderators are now able to remove members from list

src/main/java/de/srsoftware/widerhall/web/Web.java

@@ -5,7 +5,6 @@ import de.srsoftware.widerhall.data.ListMember;
 import de.srsoftware.widerhall.data.MailingList;
 import de.srsoftware.widerhall.data.Post;
 import de.srsoftware.widerhall.data.User;
-import org.json.simple.JSONObject;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -296,7 +295,7 @@ public class Web extends TemplateServlet {
 
         if (!error && !list.mayBeAlteredBy(user)) {
             error = true;
-            data.put(ERROR,t("You are not allowed to alter this list!"));
+            data.put(ERROR,t("You are not alter settings of this list!"));
         }
 
         if (!error){
@@ -305,6 +304,7 @@ public class Web extends TemplateServlet {
                         .forwardAttached(Util.getCheckbox(req, KEY_FORWARD_ATTACHED))
                         .hideReceivers(Util.getCheckbox(req, KEY_HIDE_RECEIVERS))
                         .replyToList(Util.getCheckbox(req, KEY_REPLY_TO_LIST))
+                        .modsMayNominateMods(Util.getCheckbox(req, KEY_MODS_CAN_EDIT_MODS))
                         .openForGuests(Util.getCheckbox(req,KEY_OPEN_FOR_GUESTS))
                         .openForSubscribers(Util.getCheckbox(req,KEY_OPEN_FOR_SUBSCRIBERS))
                         .archive(Util.getCheckbox(req,KEY_ARCHIVE));
@@ -483,9 +483,22 @@ public class Web extends TemplateServlet {
                 return loadTemplate(UNSUBSCRIBE,data,resp);
             }
         }
-        // if we get here, we should have a valid user
+
+        ListMember member = null;
         try {
-            ListMember.unsubscribe(list,user);
+            member = ListMember.load(list,user);
+        } catch (SQLException e) {
+            LOG.debug("Failed to load list member for {}/{}",user.email(),list.email(),e);
+            data.put(ERROR, t("Failed to load list member for {}/{}",user.email(),list.email()));
+            return loadTemplate(UNSUBSCRIBE,data,resp);
+        }
+        if (member == null){
+            data.put(ERROR, t("{} is no member of {}",user.email(),list.email()));
+            return loadTemplate(UNSUBSCRIBE,data,resp);
+        }
+        // if we get here, we should have a valid member object
+        try {
+            member.unsubscribe();
             data.put(NOTES,t("Sucessfully un-subscribed from '{}'.",list.email()));
             return loadTemplate(INDEX,data,resp);
         } catch (SQLException e) {