SourceForge Updated

It was pointed out that SourceForge itself still directs users to the older 2.5 release rather than the funky up-to-date 2.5.1 edition.  I’ve fixed it and, while I was doing so, noticed that the summary page was looking a bit tired and out of date so this has had a spruce up with the inclusion of some more recent screenshots.  Check it all out at https://sourceforge.net/projects/snarlwin/