Add an option to show/hide the startup Welcome menu from the mintDesktop tool

It would be nice if the option to show/hide the startup Welcome menu after you login (the informational one that lists links to the New Features, PDF Manual, etc. and also shows the distro metainformation) from the mintDesktop tool, using a simple checkbox, similar to the way the Terminal fortune cookies were added as a selectable option to the same mintDesktop tool in Linux Mint 11 Katya.

I suppose that there are folks out there that sometimes feel like bringing that Welcome menu back once they've chosen not to show it at login (using its in-window checkbox), so this option returns the choice of whether or not to use that feature, using the mintDesktop tool.