BSChart column data gets shifted on y-scale in Followers example

[jumbopilot]

Hi Blacksus,

I find your BSChart library pretty good designed.
However, I’ve noticed an issue in the Followers example.

While adding/removing the "joined" or "left" line data column, the "joined" line gets vertically shifted due to min/max values on the graph line. Thus, in single line vs. dual line mode display, the graph line does not match the y-scale (remaining fix).

Hope this helps you improve the graph and auto-layout.