Added http reader that work with cross-origin resources

Hi, I've created file HttpRangeReaderCORS that allow to download zip content from a cross-origin domain. 
It require to put a proxy.html file on remote site, containing the instruction 

        zip.fs.initCORSProxyServer("<allowed origin>");

This proxy file has than to be put on a iframe in the page where we want to retrieve the zip content.