Add Restart link to installer

During installation, if you need to change any of your previously entered settings or want to restart for any reason, you must manually delete /store/install_config.php. This is confusing for new users and they must come post in the support forum asking how to go back a step. It would nice if there could be a way to go back to a previous step, or at least a link/button that deletes the file to restart the installation process.