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

* Adjusted doc for autoscaling; ref Issue #2540

* Edited Defaults column for Min/Max options for completeness

* 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

dataColor.fill and dataFill.stroke had wrong descriptions.

* Add the source data to Point3d objects in Graph3D; This allows more complex tooltips, using information sent from the server + the source object
* Update PR as requested
* Convert tabs to spaces; Vim config was off, edited in sublime instead

Added a "showLegend" option which can be used to toggle legend drawing
Added legend drawing to 11_tooltips and to playground examples
Added description of showLegend option to documentation

see #909