tomicheck

Results 2 issues of tomicheck

Hi, I've just upgraded to 4.2 (BrewPiLess.v4.2.rc2.oled.esp8266.4m2m.bin) and I can see iSpindel gravity readings on OLED: ![20220506_001338](https://user-images.githubusercontent.com/105049792/167114977-3ba9e399-810d-4f23-bd0e-0355f2bad334.jpg) and on testcmd.htm: ![Screenshot_20220506_001437](https://user-images.githubusercontent.com/105049792/167115303-7cad4b41-c84c-4268-aaed-594b4c227a83.png) but they are missing in the graph: ![Screenshot_20220506_001101](https://user-images.githubusercontent.com/105049792/167115565-20da0436-3889-4853-ad66-fe23cf5e0035.png)

During the fermentation of saison the gravity readings in Plato dropped down to small negative values that are incorrectly plotted as around 326˚P ![image](https://user-images.githubusercontent.com/105049792/216706142-b37fbaa5-5270-46ba-af27-1831ff6d201f.png)