Wind speed and direction preset doesn't work

Math functions wrap_360 and atan2 are not defined.
Fix that worked for me, define these functions in /src/mavextra/mavextra.js:

```
window.atan2 = Math.atan2

window.wrap_360 = function (a) {
let w = a % 360
if (w < 0) w += 360
return w
}
```

Open src/mavextra/mavextra.js and start by reproducing the wind speed and direction preset. Check the reported undefined wrap_360 and atan2 errors, then verify that the preset loads and displays wind speed and direction without those errors.

Written by the indexing model from the issue text.