Registry.Create<T>: shortcut for  Registry.Factory.Create<T>
Xwt.WPFBackend.DataConverter: nullcheck nativeImage
rename TextViewerRtfType=>TextViewerTextType | move Iconery to namespace Limaki.Iconerias | cleanups
WpfBackends.LayoutToolStripBackend implemented
Limaki.View.XwtWpf: TODOs checks
WpfBackends.ToolStripDropDownButton: show tooltips in popup window