Test startup timeout issues in usb tool on Mac and Windows

[jeffstjean]

In usb/usb_tool.js, the startup() routine is invoked through a setTimeout when a new USB device is added. Determine if this issue exists on platforms other than MacOS (Windows, Linux) and see if there's a cleaner solution to the issue.

usbDetect.on('add', function(usb_port) { 
    if ((usb_port.manufacturer.toLowerCase().includes('arduino')) || 
            usb_port.manufacturer.toLowerCase().includes('teensyduino')) {
                // usb-detection seems to discover devices before SerialPort has access to them
                // not the prettiest solution but adding a small delay resolves these issues on Mac
                // TODO: test to see if these issues occur on Windows and Linux
                setTimeout(startup, 500);
    }
});