TTY terminal output is unavailable on CI, or when users redirect output to a file or a pipe. In those cases `TerminalController` initializer returns `nil`. SwiftPM has a wrapper `InteractiveWriter` class for it, which writes output to stdout directly in that case. I've copied that, and replaced all uses of `TerminalController` with it. A VSCode task is added to test that.
In my testing it looks like download progress reporting is quite spammy, so it now has `removeDuplicates` Combine operator added to make it output only when values differ significantly from each other.
Additionally, SDK installs can hit GitHub API rate limit on CI nodes, so `carton` now reads `GITHUB_TOKEN` environment variable, which gives much higher limits to authenticated API users.
We can now also run various `carton` commands on CI for basic end-to-end testing.
Resolves#112.
The latest SwiftWasm 5.3 snapshot requires users to use `import WASILibc` instead of `import Glibc`. This makes differences between platforms more explicit.
Max Desiatov