Add visual indication of encoder stepsize

[fietser28]

From the display you can't see the encoder step size (without also changing it). I often find myself needlessly cycling thru encoder stepsize because I wasn't sure about the set setpsize and I don't want smoke because of a sudden big step. Conformation mode works for steps, not slowly going up/down for me.

Adding a small marker below (1 step), or above (5 steps) is a nice reminder for this. Shown below: Encoder stepsize is at 100mV:

Encoder setpsize is at 50mV:

The bars should align with the numbers and if the setpsize is small the number needs to be shown. This relates to #144

[electrokean]

Great idea!