Option for a function to customise the y-axis labels

[adampope]

I'm drawing bar graphs where the bars represent an amount of time. I'm passing in the time as a number of minutes e.g. 600. This is then used on the y-axis scale. I'd like to be able to supply a function which can format this value (e.g. into 10hr) when it is displayed on the axis.

Apologies if this has already been done, I've had a look through the closed issues and couldn't see it, but I can see you've done a lot of work compared to the documentation on the website.

[oesmith]

See the solution in #139. This will be released in v4.0!