code: function findBlinkSticks (filter) {
      if (filter === undefined) filter = function () { return true; };
  
      var result = [], device, i, devices;
  
      if (isWin) {
          devices = usb.devices();
  
          for (i in devices) {
              device = devices[i];
  
              if (device.vendorId === VENDOR_ID &&
                  device.productId === PRODUCT_ID &&
                      filter(device))
                  {
                      result.push(new BlinkStick(device.path, device.serialNumber, device.manufacturer, device.product));
                  }
          }
  
      } else {
          devices = usb.getDeviceList();
  
          for (i in devices) {
              device = devices[i];
              if (device.deviceDescriptor.idVendor === VENDOR_ID &&
                  device.deviceDescriptor.idProduct === PRODUCT_ID &&
                      filter(device))
                  result.push(new BlinkStick(device));
          }
      }
  
      return result;
  }
docs: Find BlinkSticks using a filter.
  
  @method findBlinkSticks
  @param {Function} [filter] Filter function.
  @return {Array} BlickStick objects.