Put publish date in about with release

[micheus]

The version is already there in the About (splash window). I'm not sure if it's possible to automatize the insertion of the build date (do that by hand will not work), but it should.

I'm going to take a look and ask dgud about that.
I've been working in a new layout for it in order to allow us to include an image and then - before any new release - we can promote a splash screen challenge, as suggested by the user Hank in his post.