Timestamp axis support

[kdkavanagh]

Curious if you have any recommendations on how I might use timestamps as the values for the x-axis? Thinking I could convert to epoch seconds, but then would need a way to convert back to human-time for the axis labels - Perhaps a tick-labeller callback? Ideally on "round" timestamps as well

[davidfokkema]

Yes, this should be high on the feature list. It is a bit of work, see e.g. https://matplotlib.org/stable/users/explain/axes/axes_units.html and the locaters and formatters that are mentioned there. I will work on this.

First step, I think, is adding the possibility to supply the exact tick positions and their labels to put on an axis instead of the default autogenerated ones.

[davidfokkema]

Added AxisFormatters support with a DurationFormatter which autoscales from seconds to years. No timestamps per se, but that will be next!