Add AnalyticsScreenTimer and track more screens.

Update Analytics with new methods in MXAnalyticsDelegate.

Riot/Modules/Room/Members/RoomParticipantsViewController.m

@@ -265,6 +265,8 @@
         [contactsPickerViewController destroy];
         contactsPickerViewController = nil;
     }
+    
+    [self.screenTimer start];
 }
 
 - (void)viewWillDisappear:(BOOL)animated
@@ -281,6 +283,12 @@
     [self searchBarCancelButtonClicked:_searchBarView];
 }
 
+- (void)viewDidDisappear:(BOOL)animated
+{
+    [super viewDidDisappear:animated];
+    [self.screenTimer stop];
+}
+
 - (void)withdrawViewControllerAnimated:(BOOL)animated completion:(void (^)(void))completion
 {
     // Check whether the current view controller is displayed inside a segmented view controller in order to withdraw the right item