Allow multiple select in autocomplete

This patch will update of both display and hidden related element field.
Values are separated with comma.
Rename variable since $ sign typically denotes a jquery object
Prevent XHR request when query length does not satisfy minLength
Merge branch 'pr/553' into 2.2

* pr/553:
  Prevent XHR request when query length does not satisfy minLength
  Rename variable since $ sign typically denotes a jquery object
  Allow multiple select in autocomplete

Closes #553
Hierarchy: Add breadcrumbs to display active type
Enable Controllers extending Nodes to have better experience

- The name Nodes are not hardcoded for better flash messages
- DOM Ids are not hardcoded and can be overriden via data API
BulkProcess: Redirect to referer
Merge branch '2.2-bulk' into 2.2

* 2.2-bulk:
  BulkProcess: Redirect to referer
  Enable Controllers extending Nodes to have better experience
Create Dashboards plugin to show dashboard boxes.

If Dashboard plugin is not enabled, fallback to ExtensionsDashboards
Add a setupAdminDashboard event
Render dashboard boxes into two columns and a full width column
Trigger event before and after dashboard box render
Add dashboard table to save custom user dashboards
Show some feedback on collapsing a dashboard box
Allow custom sorting of dashboard boxes
Save dashboard box location to database
Load up saved dashboard positions + constant for each column
Some pretty styling when dragging boxes around
Add an example dashboard block.
Remove deprecated Settings::admin_dashboard()