For time series charts it may make more sense to specify the horizontal axis using the variable `t`. This change will make it much easier to use the time scale with the financial chart, which takes in the data points `{t, o, h, l, c}`.
The title plugin and scale title now accept lineHeight specified using unitless value (1.4), length ('1.4em' or '12px'), percentage ('200%') or keyword ('normal' === 1.2). The line height parsing has been refactored under the 'Chart.helpers.options' namespace. Also fix incorrect text positioning in the title plugin.
https://developer.mozilla.org/en-US/docs/Web/CSS/line-height
* Fix relative links in documentation of configurations
* Fix relative link of 'Time Units'
* Fix relative links for chart types documentations
* Fix the release version link in developers/plugins
* respect new scale option 'order' when ordering scales
* scale service - respect new weight scale option for axes ordering
* added test for scale ordering by weight
* removed trailing spaces from layout weight scale order test
