Feature request: Track hue max min feature

[mhasting2004]

I think it would be very nice to have the ability to set the max min values of the track hue. In this way things like heartrate could be visualised better for us unfit people that have higher resting rates or those that want to see more subtle altitude variations because we dont live in the alps.

I also do still think that the heartrate font colour in the meters should also be related to these color values

Thanks Mark