* Timeline:
* Add overrideItems sub-property to timeline.editable
* Change behavior to override item.editable when overrideItems=true
* Added new example for timeline/editing to higlight differeing editable behaviors.
* Update timeline doc to reflect addition of timeline.editable.overrideItems
* Timeline - fixed logic oversights found in editable override testing
* Timeline - enable changeGroup when item.editable = true and not overriden
* Timeline - Small format changes to documentation and example pages for overrideItems

* Add initial onChange item tooltip
* Add example and tooltipOnItemEdit template option
* Add docs and rename option
* Fix docs
* Fix example
* Change example's item types
* Fix point item tooltip
* Fix comments from PR and support bottom orientation properly
* Add semi-colon

@simo9000 Thanks!

* Add initial experiment
* Register drag and drop events
* Add initial drag and drop support
* Add drag and drop support for all types of objects
* Fix example
* Clean up code and add comments
* Fix example
* remove font awesome
* Fix example style
* Add meta tag to example and add selected when dropped

* 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

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

added docs

Timeline will check for the property 'editable' on individual items.

  if editable === true
    ignore timeline option 'editable'
    allow item to be edited
  else if editable === false
    ignore timeline option 'editable'
    do not allow item to be edited
  else
    use timeline option 'editable'

If two items are selected and one is not editable, only the editable
item is draggable.

This change required the css class .vis-editable be moved from the
item set to the individual item containers to maintain proper styling.