Add support for --proxy-bypass-list command line argument

[etiktin]

Depends on electron-archive/brightray#179

Explanation copied from the brightray PR:

This PR adds support for the --proxy-bypass-list command line argument. It enables you to decide on hosts that should bypass the proxy server set by --proxy-server. For example if your app talks to a local web server (e.g. http://127.0.0.1:8080), you probably don't want it to go through the proxy server (how will it resolve 127.0.0.1 to the correct host?), so you can use --proxy-bypass-list="127.0.0.1:8080" or the more general --proxy-bypass-list="<local>".
The value can contain more than one host, separated by semi-colon. See examples at: https://www.chromium.org/developers/design-documents/network-settings

This PR adds the documentation for this feature.

[zcbenz]

👍