Improve documentation for Dataset creation & use

[mindok]

Documentation for preparing data for use in the charts isn't clear. Update to show full use cases, and also to discuss mapping system

[k-cross]

This is still painful. I've been going through the code and also realized that some of the functions I'm trying to use don't actually exist haha.

When I figure it out, I'll submit a PR to update some docs to make at least the PointPlot a little more clear for a particular use case. It's been a bit of a struggle figuring out how things should be formatted in order to get the desired output but at least I have a graph!

A question though, might you be nearing completion for another release, I'm wondering if I should start experimenting with the master branch instead of a release? Thanks for the library, it's really awesome to be able to visualize data!

[mindok]

Hi @k-cross - apologies if the docs don't quite line up - I'm not sure how functions for docs would become detached tbh - we're using the Elixir default documentation approach which, in theory, keeps everything nicely lined up. Would be good to see a couple of examples of where it has broken.

There aren't a whole lot of changes in master since v0.3.0 release - there's a minor change to make the SVG output work where it is referenced as file rather than inline, some default styles in case the expected CSS is missing and custom tick formatting in PointPlot. I've been trying to get to a bit of a campaign over the last few months but the day job has gone crazy - the end of the busy period seems to be approaching so hopefully soon... (e.g. by end of Oct)