Fixes#180
Changes from using `vscode` to `@types/vscode` for the majority of extension samples. The `@types/vscode` package is much smaller and does not pull in any dependencies.
Other changes:
- Remove so empty test files
- Bump engine versions to match @types/vscode versions
- Use `npm run compile` for most `vscode:prepublish` scripts
To keep things simple, this doesn't use the nls-dev package. I think this demystifies a lot of things when you see what is actually going on behind the scenes.
