Example for 8Bitdo SN30 Pro

Using Xinput on SN30 Pro,  X and A buttons are next page and B is previous page.

Couldnt figure out evtest so this is what i got working with help from google, its better than no example.

```
prevPage EV_KEY BTN_SOUTH 0
nextPage EV_KEY BTN_EAST 0
nextPage EV_KEY BTN_NORTH 0
```

I guess this isnt correctly placed under Issue but im not that versed in Github.