Fix proposal for issue #2842

More details here : #2842

* 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 #2795 issue

* Fix redraw order

* Fix error when option is not defined

* Allow template labels

* Add .travis.yml file

* Add experiment travis code

* Fix react example

* Add animation options for zoomIn and zoomOut

* Fix background items when orientation top

* Fix for issue #2536

* Adjusted documentation for fix.

* Adjustments due to review

* Grrrrr whitespace

* Fixed Travis issue

* Fix redraw order

* Fix error when option is not defined

* Allow template labels

* Add .travis.yml file

* Add experiment travis code

* Fix react example

* Fix events returned from mouse events

* Fix example

* Rename censor to stringifyObject in example

* Added support to supply an X2 to bar charts to have them scale

* Fixed graph2d stacking issue.  It no longer takes into account hidden items

* Changed x2 to end per recommendation and added this to the docs

This addresses #1982 and #1417.

It possibly reduces performance, but correctness seems better.

* Improve the performance of the network layout engine

Short-cut the execution of a number of methods in LayoutEngine to make them
handle highly-connected graphs better.

* Demonstrations of layouts of large networks

Clean up and centralise edit status for Timeline Items.

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix react example
* Add toggleRollingMode option
* Update docs with toggleRollingMode option

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix react example
* Fix bug in item editable

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix react example
* Make items z-index default to 1

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix react example
* Add animation to onUpdateTooltip

* 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

* change setCustomTimeTitle title parameter, Now could be an string or a function
* Fixed indent and spacing

* Replaces instanceof Object checks with typeof to prevent cross tab issues.

* Adds missing space.

* removed NOTICE file

* updated license date range to include 2017

* chore(docs): updated support team members

* maximum width constraints must be violated by long words. Fixes #2604.

* chore: moved examples/network/_tests/maximumWidthEdgeCase.html to test/network/

fixes #2640

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix react example
* Fix zoom below 1ms bug

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix react example
* Fix mousewheel while dragging item bug
* Return removed lines

Using the 'directed' sort method, the layout engine seemed to ignore treeSpacing (or only apply it to the first tree). This would also lead to trees colliding with one another, and having their nodes tangled in space. This complaint surfaced in a couple bugs, including #2494. This should be a step toward fixing that. For whatever reason, this code never runs when using the "hubsize" sort method.

Fixes default end, and reduces duplicated code. Adds tests.

* self reference edge should now appear in all cases
* add checks for shape width being NaN to get correct circle data
* reorder resize arguments in Diamond, Dot and Star

* fix #2613 with if statement, and null for pointer value rather than referencing it when undefined

* removed if statement, since not needed, and updated documentation to note the null pointer property in certain conditions.

* Fix redraw order
* Fix error when option is not defined
* Allow template labels
* Add .travis.yml file
* Add experiment travis code
* Fix right click button bug when dragging item

* fix(graph2d): fix #2500 for graph2d; improves #2580

* fix(DataSet): make sure the right id-type is used internaly

This fixes a fixed strange string-number conversion issue.
It can happen that id "0" !== 0 what causes #2580.

fixes #2580

* Fix redraw order

* Fix error when option is not defined

* Allow template labels

* Fix #2538

- Also updated docs and examples for this
 - Fixed the positioning of the tooltip if groups was enabled
 - Removed missing parameters from Popup docstring

* Fix redraw order

* Fix error when option is not defined

* Allow template labels

* Fix boolean types bug

* Add subgroup stacking

* Almost finish subgroup stacking

* Play with examples for subgroup order

* Fix stacked subgroups

* Fix subgroup stacking

* Add stackSubgroups option

* Fix example

* Add docs

* Fix onRemove item subgroups recalculate

* Return subgroup example and add stackSubgroup example

* Split stackSubgroup example to subgroup/html and expectedVsActualTimesItems.html

* Fix small bug when subgroups start overlap