* Fix mergeOptions() and add unit tests

* Removed comment

**Note: ** This is a simple fix and should be easy to review.

Fix for #2579

- Adjusted node title definition in `options.js` to allow DOM elements
- Changed `BridgeObject()` in `util.js` so that DOM elements are *not* bridged.

Fix for #2856

- Toolbar gets reshown when cancelling edit node dialog
- No shadow displayed upon save in edit node dialog

The latter is actually a more general problem. Function `mergeOptions` in `util.js`
made an assumption as to the correct value of field `enabled`. It now takes the value
from `globalOptions`, if present.

* Add support for multiple class names in utils add/remove class methods.
Reset subgroup heights in resetSubgroups method.

* Adjust to better process class names

* 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 selectiveExtend accept null/undefined parameters

* 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

Fixes: #2490 (on the correct branch this time)

* element characteristic changes
* assume edge color inheritance is correct before choosing
* Adjust nodes’ chosen’s boolean -> bool
* Need to get user-reset size
* make example edges thicker for more noticeable shadow
* preemptive ES6 fix (see #2500/#2501)
* documentation for the feature that was previously overwritten

Fixes: https://github.com/almende/vis/issues/2490

* Fix redraw order
* Add elements censor and event to emitter
* Fix all recursive loop in json event
* Add docs for event emitted

* Multifont node and edge labels
* adjust documentation
* rework mod-font property inheritance
* Node max/min widths, min heights; Edge max widths
* Accumulate sizes correctly for unconstrained multipoint labels
* handle font.multi when groupOptions.font is not declared
* propagate label fonts on changes, not just creation
* Allow top-level constraint numbers
* accumulate width and empty lines appropriately

* Add initial scroller without options
* Add initial scroll without an option
* Add verticalScroll option
* Fix scrollbar positions
* Add docs
* fix example
* remove jquery dependency
* Fix example
* Fix review comments

- Fixed #1528, #1278, avoided ID's being cast to string for methods that return ID's as well as storePositions casting to string.

Provide the DataView.map() method similar to the DataSet one.

Added the following:
- dashes property to nodes in options.js
- dashes property with value false to defaultOptions in NodesHandler.js
- support for Arrays to selectiveNotDeepExtend function in util.js
- functionality to CircleImageBase.js that allows circularImage nodes to have dashed borders
- example demonstrating how to apply the dashed border to a circularImage node
- documentation explaining the usage of the dashes property on a node

- Dropped support for appending data returned by `DataSet.get()` to an existing Array or DataTable.
- Fixed a `window` issue in uuid.js.