[IZPACK-1150] - Uninstaller should properly handle .installationinformation and auto-install file

1. If .installationinformation file is created it is added to the UninstallData
2. If a automatic install file is created and placed into the $INSTALL_PATH it is added to the UninstallData
3. Message on prompt that appears when failing remove certain files/directories has been updated to indicate that directories may have not been removed if they were not empty