Modified desktop entry so that Sublime Text shows in "Open With..." dialog

I'm using Sublime Text from your overlay (thank you!) and want to propose a simple enhancement.

The problem with current .desktop file generated for Sublime is that it does not show up in "Open With..." dialog in Nautilus. Changing `Exec=subl3` to `Exec=subl3 %F` fixes this, as explained for example here: http://ubuntugenius.wordpress.com/2012/06/18/ubuntu-fix-add-program-to-list-of-applications-in-open-with-when-right-clicking-files-in-nautilus/