remove workspace file
extract common desktop app code from main
missed some TK name changes
Make color screen a slave

This way we don't have to have 2 copies of each window
divide drawing into parts for easier overriding
don't ref/unref represented object
better handling of drawing children of focused widgets
cleanup some layouts
add Menu widget

also fixes some memory leaks with Container
fix memory leaks in CheckButtons
fix leak in scroll demo
fix vertically centered wrapped text in labels
add separate strong represented_object to Widget
add CheckboxMenuItem
expose label widget in MenuItem
add font demo

includes chaning default font, widget drawing performance improvement,
fix scrollbar indicator issues, convert demo main menu to Menu widget