* 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

fixes #2685

* 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

Related to: https://github.com/almende/vis/pull/2618
Related to: https://github.com/almende/vis/pull/2620

* 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.

If you want to integrate the vis.js sources in a project you need some babel-pugins.

see #2353

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 react example