Modified the get_url module to respect the content-disposition header if the destination is a directory and the server provides it.
See http://www.w3.org/Protocols/rfc2616/rfc2616-sec19.html, section 19.5.1.
Use the final URL from the finished request instead of the provided URL for filename generation, to properly deal with redirects.
Merge pull request #4785 from Tinche/get_url/uri-content-disposition

Modified the get_url module to respect the content-disposition header if...