1.7.1.0

Fixed an issue where something goes absolutely sideways and removes the entire game directory. I'm kinda glad this just happened to me, and no one reported it, but if it did happen for anyone, I sincerely apologize.

Mostly this was changed by moving the entire section where it downloads the file and extracts it to its own separate function, and commenting out any references to "Remove-Item". So the -dlkeep flag won't work for now.

Also changed from relying on an existing install of 7-zip to the 7zip4Powershell module (https://www.powershellgallery.com/packages/7Zip4Powershell/).