* TemplateSaveError -> CardTypeError
* Don't show success tooltip if export fails
* Attach help page to error
Show help link if export fails due to card type error.
* Add type (dae)
* Add shared show_exception() (dae)
- Use a shared routine for printing standard backend errors, so that
we can take advantage of the help links in eg. the card layout screen
as well.
- The truthiness check on help in showInfo() would have ignored the
enum 0 value.
- Close the exporting dialog on a documented failure as well
* Fix local variable help_page
