Hello Andrew,
Let's distinguish between 3 different elements:
1. The viewWindow - this allows you to control the visible range of values on the axis.
In your case, if you set the minimum to 1 (instead of the default 0) then a bar with the value 1 will have a height of 0.
2. The gridlines - these are the gray lines you see. At the moment these are not configurable, but we are considering allowing the user to specify them in the future.
3. The baseline - the black line that the bars rise from.
My guess is that in your case you would simply like the label '1' next to it. If this is so, please open a feature request asking to specify the value of the baseline next to it.
HTH,
Visigoth