* Enable cross-compilation and packaging of Windows Appx from macOS
* Consolidate cargo build execution into a single function in native build script
* Install cargo-xwin when needed
* Install Appx tools when needed
* Consolidate command execution into a single function in native build script
* Only include the native node modules for the appropriate platform
electron-builder's globs interact strangely, so we can't
exclude all the .node files in the global config and then
include the platform-specific files in the platform
configuration.
* Always copy Rust binaries to dist folder
* Log source and destination when copying files
* Update copyright
* Match Electron version in Beta build
