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

* Adds missing space.

* 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

* Important performance enhancement supporting incremental changes to large graphs, these were too slow due to doing a full item conversion on each add().
Note: the data handling side of graph2d is currently somewhat over-engineered (=too complex) It can use some simplification....

* Fixed style based on feedback.

* Updates all 'remove' events in DataSet and DataView to include the objects that were removed in addition to the the ids.
* Updated the documentation to reflect changes.
* Fixed possible object mutation when typeof id is object in DataSet.remove.

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

Added functionality to extend the fields array, to a fields object,
similar to the type declaration. This makes it possible rename
properies when you get them.