Changes to allow the tooltip for thumbnails to be updated by metadata
Changes to allow the tooltip for thumbnails to be updated by metadata

- if metadata changes or new metadata is made available, thumbnail tooltip
  is now updated

naojsoft/ginga,pllim/ginga,ejeschke/ginga,naojsoft/ginga,pllim/ginga,naojsoft/ginga,ejeschke/ginga,ejeschke/ginga,pllim/ginga