improving autorelease memory handling

life sample was using up memory when running in a tight loop, because the normal event autorelease pool was never reached

src/osx/cocoa/stattext.mm

@@ -93,6 +93,8 @@ public:
 
     virtual void SetLabel(const wxString& title, wxFontEncoding encoding) wxOVERRIDE
     {
+        wxMacAutoreleasePool autoreleasepool;
+
         wxCFStringRef text( title , encoding );
 
         NSMutableAttributedString *

src/osx/cocoa/window.mm

@@ -3070,6 +3070,8 @@ void SetSubviewsNeedDisplay( NSView *view )
 
 void wxWidgetCocoaImpl::SetNeedsDisplay( const wxRect* where )
 {
+    wxMacAutoreleasePool autoreleasepool;
+
     if ( where )
         [m_osxView setNeedsDisplayInRect:wxToNSRect(m_osxView, *where )];
     else