This package is identical 1.4.1-pre2 with an update to all portable libraries to now target Profile 259

• Secondary toolbar items on iOS now have a disabled appearance
• Add PREVIEW (unsupported) Xamarin.Forms.Windows package to the family.

• Bug 27782 - Hard crash, as soon as a item in a ListView is selected and then changed
• Bug 27765 - Labels misaligned inside of ViewCells (and everything else actually)
• Bug 26418 - [Android] ListView does not update when the bound ObservableCollection changes
• Bug 27304 - Toggling IsVisible for an element in a Grid row does not update properly
• Bug 27625 - ListView cell with multiple labels height crops content
• Bug 27085 - EntryCell has no possibility to hide keyboard on iOS
• Bug 26771 - [Android] jobject must not be IntPtr.Zero when Navigation.PushAsync after resuming app
• Bug 27301 - Bug in ToolbarTracker.UntrackTarget
• Bug 26487 - WebView local files fail within WinPhone
• Bug 24484 - NavigationRenderer.ParentingViewController breaks things
• Bug 27429 - App lifecycle OnResume event called multiple times in tabbed app (one time per tab) in Android

• Switch.IsToggled on Android no longer resets bindings by mistake.
• Fix potential crash in iOS WebView