Add flag to check whether an item in the Itemset is currently being dragged

Resolve issue #1857 Fixed node positioning with improvedLayout:true

Improvements for graph3d legend support

Fix incorrect documentation URL

Perturbing the nodes was being performed on all nodes regardless of whether they were set as fixed.

fix known security issue with handlebars version

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

It was broken by PR (#1729), which fixed issues #112 & #1730.
As far as I can tell that change shouldn't influence the DataAxis (vertical-axis), but only the horizontal axis.

 @yotamberk can you check if your examples still work as expected?

Set content width to avoid overflow (Fix #1853)

reset switched{Day,Month,Year} in next function, not in isMajor function

BugFix - Network.options.nodes

Fixed updating directions of the arrows with the string type

As the documentation on vis.js nodes can be styled with align: left|center

allOptions does not include this option and throw an error on option validation.

`vis-network.min.js`, and `vis-timeline-graph2d.min.js`