Linux and macOS support

[johanneszab]

Woa, Microsoft is really going wide with multi-platform support after the acquisition of Xamarin. They make .NET core, standardized XAML and now Xamarin.Forms 3.0 seems to support Linux and macOS as well. From judging the repository the code has already been landed.

The current GUI is written in WPF which uses XAML. Maybe it's possible now (soon) to not even only share the underlying application (domain, application logic) but also most of the user interface for a Linux and macOS version.

[johanneszab]

Follow-up to #62 and #1.

[johanneszab]

There is a second cross-platform GUI framework using XAML (WPF) for .NET core, called Avalonia

Example project:

• Cross-platform falling snow demo on .NET Core and Avalonia UI by Pavel Tupitsyn.