usb_serial_for_android library

1. usb_serial_for_android package
2. documentation
3. usb_serial_for_android.dart

usb_serial_for_android package

1. Libraries
2. equality
3. transaction
4. transformers
5. types
6. usb_device
7. usb_event
8. usb_port
9. usb_serial_for_android