Trend Tracking

There is space and support on-screen for a trend arrow - a new feature that was identified as useful during the initial medical feedback.

The desire would be for 1- to 10-minute trend information. This needs careful design to ensure that memory consumption is not massive.

Once calculated, trend markers to be added using oled.drawChar(116,0,UPARROW,2) - using UPARROW, DOWNARROW or '-' as required.