3 updates mainly around how problems, with various connections, are displayed to users.
1) Proxy details not entered, causing login failure. Now displays a better error message with hyperlinks to PRIDE website.
2) TCP 22 blocked, unable to obtain login credentials, causing no response when 'submit' button is clicked. Now handles this case, and displays a better error message.
3) UDP 33001 blocked, unable to start Aspera transfer. Now displays a better error message, and automatically attempts again with FTP instead.