Add asinh scale

[apcamargo]

The asinh transformation is useful for figures that have 0 values. It is very similar to log and works fine with 0. Other popular libraries, such as ggplot2 and Matplotlib, provide this scale.

[alshan]

Hi, try using 'symlog' transform on a scale: scale_x_continuous(trans='symlog').

[apcamargo]

Hi Igor Alshannikov (@alshan)

That's what I've been using, but it's not as elegant as asinh as the transformation is not uniformly applied throughout the axis. In some cases, having a linear region around 0 can look strange.