Highlight all values

[jmartingit]

(Feature request)

It would be great to have a 'setHighlightAllValuesEnabled(boolean)' method, to indicate that we want to highlight all values in the chart, without the need to pass an array of Highlight objects.

Currently, if the chart contains a lot of values, we need to create a lot of Highlight objects and pass them to the 'highlightValues' method. But if the chart knows in advance that we want to highlight all values, that shouldn't be necessary.

That would save precious memory and processing time.

(If there's already another way to achieve this without creating a lot of Highlight objects, please someone let me know)