Modify series and yAxis

[mtabacman]

series and yAxis by default return a new element the first time, and the same element when called again.
They should be changed to return a collection and never add a new element.
We should also create news methods addSeries / addYAxis which return a new element, and add them to the collection.

[marianopeck]

Hi @mtabacman

I just realized that the methods highstockAddSeriesSourceCode and highstockAddYAxisSourceCode are there in Highstock6DumpImporter but I do not see them auto-generated in the highstock package. Could it simply be that you didn't have the time to re-generate and publish a new HighstockV6 package ?

If so, then just please let me know when you were able to commit a new auto-genrated version of HighstockV6.

Thanks