Do common wxApp cleanup before port-specific part in all ports

Some ports called wxAppBase::CleanUp() before performing port-specific
cleanup, while some did it afterwards. The former seems preferable, as
some actions performed in wxAppBase (such as showing log dialogs) may
not work any more after the port-specific cleanup is done, while there
should be no dependencies in the other direction.

So standardize on calling wxAppBase version first in all ports, which
also makes them more consistent with each other.

src/gtk/app.cpp

@@ -568,6 +568,8 @@ bool wxApp::Initialize(int& argc_, wxChar **argv_)
 
 void wxApp::CleanUp()
 {
+    wxAppBase::CleanUp();
+
     if (m_idleSourceId != 0)
         g_source_remove(m_idleSourceId);
 
@@ -577,8 +579,6 @@ void wxApp::CleanUp()
         g_type_class_unref(gt);
 
     gdk_threads_leave();
-
-    wxAppBase::CleanUp();
 }
 
 void wxApp::WakeUpIdle()

src/osx/carbon/app.cpp

@@ -358,13 +358,14 @@ int wxApp::OnRun()
 void wxApp::CleanUp()
 {
     wxMacAutoreleasePool autoreleasepool;
+
+    wxAppBase::CleanUp();
+
 #if wxUSE_TOOLTIPS
     wxToolTip::RemoveToolTips() ;
 #endif
 
     DoCleanUp();
-
-    wxAppBase::CleanUp();
 }
 
 //----------------------------------------------------------------------

src/x11/app.cpp

@@ -198,10 +198,10 @@ bool wxApp::Initialize(int& argC, wxChar **argV)
 
 void wxApp::CleanUp()
 {
+    wxAppBase::CleanUp();
+
     wxDELETE(wxWidgetHashTable);
     wxDELETE(wxClientWidgetHashTable);
-
-    wxAppBase::CleanUp();
 }
 
 wxApp::wxApp()