* Convert axis options from arrays to objects
* Updated all chart type defaults
* Throw errors when axis type or position are not specified
* Avoid raising unnecessary errors when merging options into the default configs
* Fix additional tests
* Ensure scale defaults are set if type is not explicitly defined
* Another step
* Include `scale` as `firstIDs.r`
* update docs
* Update for buildOrUpdateScales
* Update migration guide
* Add test back
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
