v0.1.22

Changes to allow obeying a preference of mg/dL or mmol/L for blood glucose display units, rather than trying to infer these from the data. Also various fixes for display in mmol/L - mostly to do with converting scales and rounding/formatting display values (on the settings page and in trends view highlights in particular).

Also included changing the scale for the average BG stats widget from a remnant log scale to a clamped linear scale with a domain set to the threshold for low and high BGs (defaulted to 60 and 300 in mg/dL but converted when units are set to mmol/L).