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