Should disable system-wide proxy when connected

[pelepelin]

Getting ERR_PROXY_CONNECTION_FAILED in Chrome, but connection is ok in curl.

When VPN connection is established, the system-wide proxy most probably becomes unreachable and most probably should be force disabled for privacy reasons unless it's on localhost.

Windows claims that proxy settings don't apply to VPN connections, however, it apparently does not detect that new connection is in fact VPN.

Desktop (please complete the following information):

• OS: Windows 10
• Browser Chrome 69