Fix: Chart type resets to Date/Time when editing #186
Show error message if failed deleting a visualization
Workaround for cases when widget is missing but referenced in a dashboard layout (re. #120)
Make job expiry time configurable.
Fix: return last cached result for ttl=-1 (fix #174)
Merge pull request #194 from EverythingMe/feature_markdown_widget

Several small fixes (#186, #120, #174)