Fix #1: retain fragment instance on configuration change (??)

This is probably an Android support library bug (or misinterpretation).

Signed-off-by: Daniele Ricci <daniele.athome@gmail.com>

src/org/kontalk/ui/ConversationListFragment.java

@@ -136,6 +136,7 @@ public void onSaveInstanceState(Bundle outState) {
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
 
+        setRetainInstance(true);
         setHasOptionsMenu(true);
     }