* First working version of new class DataGroup.

* Adjustments for review - done all points except last

* DRY distinct values, clean up sort code

* Added missing @param's to comments in DataGroup

Sorry for the delay on this... It took me a while to confirm this PR again. I don;t know why I didn't merge it at the time I reviewed it. Looks great to me!

* styling support for graph3d tooltips

* styling support for graph3d tooltips

* graph3d styling example, deleted new example and altered the original

* graph3d tooltip styling, documentation

* graph3d tooltip styling, use the util module's method for merging objects

* Fix for issue #2536

* Adjusted documentation for fix.

* Adjustments due to review

* Grrrrr whitespace

* Fixed Travis issue

* Added showX(YZ)Axis to Graph3d

* Added show_Axis options to docs and playground example

* Resolved merge conflict

* Added show_Axis options to docs and playground example

* Allow pass the color of points in 'dot-color' mode of Graph3D explicitly - clear the source code and finalize
* Add an onclick callback in Graph3D, to enable click and display customer user-defined information for single data point
* Extra data type validation for string conversion functions in Setings
* Disable onclick callback immediately after rotate/pan
* Re-format the JavaScript file
* No onclick event set by user - properly treat this case now
* Further reformat - indentation
* Handle the case where there is no closest data point

* fixed label disappearing bug for large axis values in Graph3d
* only fixed label disappearing bug for large axis values in Graph3d
* very only fixed label disappearing bug for large axis values in Graph3d

* Added class Range for Min/Max value pairs.
* Processed review feedback, added comments.
* Fixed jsdoc tags; reviewed commenting
* Final fixes to commenting

* Graph3d: make setting dotSizeRatio public
* Added method for dotSize
* Fixed silly indent