Release v0.9

Opening a PR to start some discussion around v0.9. What other PRs do we want in for v0.9?

Once everything we want has been merged into dev, I'll manually merge this with an additional commit to increment the version number and publish to NuGet/Chocolatey.

PRs included with this release have been marked with [the v0.9 milestone](https://github.com/scriptcs/scriptcs/issues?direction=desc&milestone=5&page=1&sort=updated&state=closed).