internal: JSAN socket library

internal: JSAN socket library

Leverages Mozilla's nsISocketTransportService, nsIScriptableInputStream, and
nsIInputStreamPump XPCOM, and the NetUtils javascript module.

    Usage example:

    Install netcat on a server and as root do:  nc -l -p 5000

    Then, in the staff client, load Admin -> For Developers -> Javascript Shell

    Enter:

    JSAN.use('util.socket');
    var s = new util.socket('server hostname or IP address here', 5000);
    s.write('hello\n');

    On the server, reply with world<enter>

    Back in the javascript shell, use

    s.read();

This is geared to help with implementing future functionality, but shouldn't
result in any end-user visible changes by itself.

Signed-off-by: Jason Etheridge <jason@esilibrary.com>