tweaking the demo layouts
Change the foreground colour of the MenuItem when disabled.

Added Input Gesture into MenuItem.

Added brush resource for disabled MenuItem and associated it.
updated demo to include a disabled form item
updated readme
added repro for issue #318
bugfix for #269 - set the RenderTransformOrigin value
#253 - providing IsCheckedChanged hook for ToggleSwitch consumers
updated sample to use event handler
Update readme.md