and some other example programs.

* examples/book/buildapp/step9/exampleappwindow.cc:
* examples/book/buildapp/step9/window.ui: Show window icon.
* examples/book/buttons/radiobutton/radiobuttons.cc: Only one pressed
button when the program starts up.
* examples/book/clipboard/ideal/examplewindow.[cc|h]:
* examples/book/clipboard/simple/examplewindow.[cc|h]: Store copied text
until someone has a chance to paste it.
* examples/book/treeview/filter_modify/examplewindow.cc: Fix some TODO
comments.