* Small refactoring in Label._drawBackground()

* Added size calculation to Label, basic framework for detecting click on label.

* First fully working version of label click.

* Put in extra checks, refactored visibility of labels for more general usage.

* Final fixes to code; added to example and in docs

* Adressed review comments

* Add next attempt to fix Travis unit test bug

* Addressed review issues

* Label performance improvements

* Label cleanup

* Fix drag performance in IE

* Fixed broken images still trying to draw

* Fixed merge and lint issues

* Corrects usage of @static jsdoc annotation

* Correct unresolvable types

* Correct types in jsdoc and remove extraneous @class & @constructor jsdoc

* Remove incorrect @static jsdoc

* Adds missing jsdoc for param copyFromGlobals

* correct jsdoc in util

* Corrects casing on jsdocs

* Swaps @inheritDoc to @ignore for constructors where constructor args are documented in the class

* Instantiates Errors with `new`

* Addresses improperly defined @callback tags.

* Split callbacks out to separate jsdoc

* Moves constructor jsdocs back to constructor and drop @ignore.

* Enables require MethodDefinition for require-jsdoc lint rule and corrects 66% of missing Method Definitions

* Adds jsdoc for all remaining methods and corrects @class/@constructor documentation

* Define values more accurately

* Correct bugs that prevent jsdoc generation

* Removes redundant .eslintrc from graph3d, lints the rest of the code base, and enables valid-jsdoc lint rule

* Corrects lint violations

Fix for #1222.

This makes the passed data of events `hoverNode`, `hoverEdge`, `blurNode` and `blurEdge`
more conformant to the passed data of the click events. In particular, the following
fields are added to the event data:

```
event: [Object] original hover event,
pointer: {
    DOM: {x:pointer_x, y:pointer_y},
    canvas: {x:canvas_x, y:canvas_y}
}
```

The changes can be tested with example `network/events/InteractionEvents`.

* Changed order of (de)select events for network

* Fixed parameters to _generateClickEvent() to be compatible with previous.

* replacing all ES6 imports with CJS require calls
resolves #2934
used the following regex to apply the changes in lib:
s/import\s+(\w+)\s+from\s+(.*);\s*$/var $1 = require($2).default;/
s/import\s+(\w+)\s+from\s+(.*)\s*$/var $1 = require($2).default;/

* cleaning up inconsistencies

* Added HTML tooltip support for Timeline

* Fixed tooltip position on Firefox

* Added Timeline tooltip example

* Updated tooltip location to be next to the mouse

* Added HTML element to example

* add pointer position to zoom event
* Update docs with zoom api

The selectEdge handler is now fired only if user clicked on an edge, in order to select it.
 It's not fired if the node are selected because there are connected to the selected node.