atkmm 2.29.1 (unstable):
Distro packagers should probably not package this yet.

Build:
* Require C++17.
  (Murray Cumming)
* Replace the Visual Studio project files with MSVC NMake project files
  (Chun-wei Fan) Merge request !1
* Use glibmm-2.60 instead of glibmm-2.56
  (Kjell Ahlstedt)
* Change the ABI to atkmm-2.30
  (Kjell Ahlstedt)