Feature proposal: overwrite target file

I would like to add a feature allowing the target file to be overwritten and thus the remote file to be re-downloaded, even if the target file exists. The current implementation skips downloading the remote file if the target file is already present.

I have created two new specs, but Ruby isn't my primary language, so I'm not quite sure I got it right (the specs ran successfully, though). My company firewall doesn't allow me to push to GitHub, so I had to copy my changes to the GitHub web editor. Hope I got everything over.

Regards
Anders L.