"Open Containing Folder" for EoG and gedit

 Bug 650402

Bug 650396

Based around Federico's recent fix to add an Open Folder functionality in Evince. Although the nautilus bug to launch nautilus file:///home/kitallis/foo.png and select the corresponding file, recently got fixed. These patches currently use gtk_show_uri() with the parent uri of the file to just launch the default file manager.