libsigc++ has moved to GitHub

We have moved libsigc++ from git.gnome.org to github.com. This should make working on it even nicer.

I’ve also moved its website to GitHub Pages rather than Sourceforge, now using the simple Jekyll templating system. But I’ve made only minimal changes, so I’d be glad if someone submitted a pull request to make the website better and prettier.

We probably should have done this sooner, because libsigc++ is in no way GNOME-specific, but GNOME’s git has been very good to us over the years and it’s been hard to trust anything else after Sourceforge fell apart. However, with GNOME’s gradual move to gitlab.gnome.org (which gtkmm will happily use) we would have to change something anyway. I am a happy (paying) GitHub user and it feels like a natural home.

I’m still rather proud of my modern C++ rewrite of libsigc++ but I’m sure it could benefit from more use than just by gtkmm 4, which is itself not used much yet. Maybe this move to GitHub will help with that.