bad description for reading keys

```
> qix-emulator --help

    -h, --help
        shows this help message
    -r, --read
        read QIX frames
    -w, --write
        **read QIX frames**
    -p, --port
        serial port
    -t, --rate
        number of keys per second (write only) - defaults to 1
    -c, --count
        number of frames to transmit (write only) - defaults to 2^64 -1
```
