Don't make the preview the default for new installs

Hello, I recently reinstalled Windows because I got an SSD for my OS drive. When I installed and ran the launcher for the first time and selected Library, it immediately began downloading the 4.7 preview. In my opinion this is unacceptable behavior. New installations should have a stable build downloaded by default (e.g. 4.6.1), with the preview builds being opt-in only.

Really. Absolutely.