Economist style ticks

[henryjameslau]

First attempt at customTimeAxis for economist style ticks

[broadpeter]

Ultimately we want to allow users to switch between Economist-style and specific points (using getXAxisTicks)

[henryjameslau]

Ultimately we want to allow users to switch between Economist-style and specific points (using getXAxisTicks)

You mean in the config? @broadpeter
I was doing it as an alternative to d3.axisBottom(x) so customTimeAxis(x) rather than using getXAxisTicks

[henryjameslau]

OK added the option into the config, although I did an alternative where I just use getXAxisTicks to get an array to pass into .tickValues and set the tickFormat to make the labels blank and then add labels between the ticks afterwards.

[nrennie]

I have no strong opinions on economist style axes, but whatever is decided - can you also add it to the two line-chart-sm, line chart dropdown, and two line chart with ci-area when it's ready?

Should getXAxisTicks() in the line-chart template be moved into the helpers.js file?

See also #361

[henryjameslau]

Ready for review

[henryjameslau]

Need this for later

[henryjameslau]

@nrennie @broadpeter @sam-ctrl Ready to review and merge. Column charts all work, custom starting months work. Had to put the readme in the lib folder as I didn't know where else to put it.

[sam-ctrl]

Ooh slick, I had a test and it's really nice. Technically it all looks good to me. I will leave it to others (@broadpeter) to comment on style etc. but to my layman's eyes that all looks good too.