message: Add comments about install libusb in the demo README
diff: @@ -20,6 +20,19 @@ CORAL_SETTING="--define darwinn_portable=1 --linkopt=-L/opt/local/lib/ --linkopt
  # Windows is not supported yet.
  ```
  +Note, the `libusb-1.0-0-dev` package is required. It can be installed as
  +follows:
  +
  +```bash
  +# On the Linux
  +sudo apt-get install libusb-1.0-0-dev
  +
  +# On the macOS
  +port install libusb
  +# or
  +brew install libusb
  +```
  +
  See the example commands in each task demo below.
  You can also explore more [pretrained Coral model](https://coral.ai/models) and
  