Merge pull request #46 from GuillaumeGomez/master

Add new dialog : FontChooserDialog
remove gtk::Widget, this shouldn't exist, use traits::Widget,
this follow my previous commit ( by mistake i've not made a pull request, see commit f985cbf10529666a68a39926521b4b920d58a305)
Merge pull request #40 from jeremyletang/rm-widget

remove gtk::Widget
New widget : UnixPrintDialog
Add new dialog : PageSetupUnixDialog (you need to uncomment it before using it)
Add new widgets : PageSetup, PrintSettings, PaperSize