minor bug in wind averaging and gusts - possibly only WMR300

[Cameron D]

Weewx 4.4.0.

I noticed recently an incorrect assumption by the weewx code - if the archive value for wind gust is less than the "wind speed" value then it sets wind gust and gust direction to be equal to the wind speed.

This is incorrect behaviour, at least for the WMR300, because the reported wind speed is actually the 10-minute average, and applies to the previous 10-minute interval, (since it can't predict the future). After the storm cell passes, for example, it is quite feasible for the current gust to the less than the "current" wind speed.  I noticed this while looking at my 92 km/h max gust recently.

I don't know how many other weather stations this situation would apply to, so it might not be of much general relevance.

In separate news, I have realised the WMR300 console does a really poor job of calculating average wind speed, so I will try to modify the driver code to allow weewx to do the averaging.