Update: Pre-release 1.7.1 has been released to address some serious crashes, including the inability to start on some Linux computers.
To help test the pre-release, open your launcher and press the “New Profile” button. Call it “snapshots” and check the box saying “Enable experimental development snapshots” and save. To switch to the normal version, you can select it in the dropdown at the bottom left corner of the launcher.
Install: On windows, right click -> open with -> java