Add "conversation settings" menu option in conversation activity.

Closes #3399
Fixes #3399
// FREEBIE

res/menu/conversation.xml

@@ -10,4 +10,7 @@
     <item android:title="@string/conversation__menu_delete_thread"
           android:id="@+id/menu_delete_thread" />
 
+    <item android:title="@string/conversation__menu_conversation_settings"
+          android:id="@+id/menu_conversation_settings"/>
+
 </menu>

res/values/strings.xml

@@ -926,6 +926,7 @@
     <string name="conversation__menu_leave_group">Leave group</string>
     <string name="conversation__menu_delete_thread">Delete thread</string>
     <string name="conversation__menu_view_media">All images</string>
+    <string name="conversation__menu_conversation_settings">Conversation settings</string>
 
     <!-- conversation_popup -->
     <string name="conversation_popup__menu_expand_popup">Expand popup</string>

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -355,6 +355,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     case R.id.menu_invite:                    handleInviteLink();                                return true;
     case R.id.menu_mute_notifications:        handleMuteNotifications();                         return true;
     case R.id.menu_unmute_notifications:      handleUnmuteNotifications();                       return true;
+    case R.id.menu_conversation_settings:     handleConversationSettings();                      return true;
     case android.R.id.home:                   handleReturnToConversationList();                  return true;
     }
 
@@ -403,6 +404,10 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
     });
   }
 
+  private void handleConversationSettings() {
+    titleView.performClick();
+  }
+
   private void handleUnmuteNotifications() {
     recipients.setMuted(0);