Handle "preview" resource button visibility according to the "deleted" status of the resource
Handle visibility of preview based on deleted status of Resource

Merge remote-tracking branch 'origin/pr/796' into release-2.2

* origin/pr/796:
  Handle "preview" resource button visibility according to the "deleted" status of the resource

Conflicts:
	manager/assets/modext/widgets/resource/modx.panel.resource.js