Minor fixes for some reported issues.
- The process now runs as an admin, to allow symlinking and avoid some other permission-related errors.
- TF2CDownloader won't exit without key input when run through Windows Terminal now, avoiding some issues where the terminal may close after the process exits.
- The butler-staging directory from any previous attempts is now always removed before patching.
- Aria2 now allows piece length changes to avoid creating problems when remote files are changed as compared to a locally-cached version.
- Non-integer input on the option select no longer crashes the application.