store subscriber list upon subscription

core/src/main/groovy/com/muwire/core/MuWireSettings.groovy

@@ -98,7 +98,7 @@ class MuWireSettings {
         
         if (!trustSubscriptions.isEmpty()) {
             String encoded = trustSubscriptions.stream().
-                map(it.toBase64()).
+                map({it.toBase64()}).
                 collect(Collectors.joining(","))
             props.setProperty("trustSubscriptions", encoded)
         }

core/src/main/groovy/com/muwire/core/trust/TrustSubscriber.groovy

@@ -46,10 +46,8 @@ class TrustSubscriber {
     
     void onTrustSubscriptionEvent(TrustSubscriptionEvent e) {
         if (!e.subscribe) {
-            settings.trustSubscriptions.remove(e.persona)
             remoteTrustLists.remove(e.persona.destination)
         } else {
-            settings.trustSubscriptions.add(e.persona)
             RemoteTrustList trustList = remoteTrustLists.putIfAbsent(e.persona.destination, new RemoteTrustList(e.persona))
             trustList?.timestamp = 0
             synchronized(waitLock) {

gui/griffon-app/controllers/com/muwire/gui/MainFrameController.groovy

@@ -218,6 +218,8 @@ class MainFrameController {
         if (row < 0)
             return
         Persona p = model.trusted[row]
+        core.muOptions.trustSubscriptions.add(p)
+        saveMuWireSettings()
         core.eventBus.publish(new TrustSubscriptionEvent(persona : p, subscribe : true))
     }