Installation of Visual Studio tools is not well integrated

[kornelski]

When installing Rust on Windows for the first time there's a wall of text, including a message saying that Visual Studio tools needs to be installed.

• Wall of text is not a nice experience, and if you don't read it, you get worse setup.
• It's a completely manual step.
• Copying of the URL from console is a bit cumbersome.

I'd prefer if Rustup had an option to at least automatically open the VS download URL. It could be the first option when user presses Enter, so user would be guided towards best solution even if they don't read the instructions.

If #253 is integrated, it'd be nice if VS install was a step in the installer.

[ctaggart]

The current installer prints this:

In my case, I have Visual Studio 2017 already installed. It would be nice if rust-init.exe launched or made it easy to launch a script that installed the required dependencies.