Give feedback when checking proxy settings

[atluxity]

It would be very useful to indicate what domain is attempted to be reached when testing the proxy setup. A lot of proxies are used with ACL for whitelisting domains, so you have to say what IP using Autopsy is allowed to connect to what hostname.

It turns out Autopsy tries to connect to netbeans.org, while I assumed sleuthkit.org

So instead of saying "Connection failed" say "Connection to netbeans.org failed".