Provide a way to delete individual elements

[ehmatthes]

Implement this on edit_sa_summary.

[ehmatthes]

Just delete, with no confirmation. Will be more fully implemented, with confirmation, on #125.

[ehmatthes]

Show the cascading list of descendant elements that will be deleted along with the element requested for deletion. Offer three options:

• [ ] Focus on deleting essential understandings first
  • [x] Cancel, and return to display/ edit view.
  • [ ] Set elements private instead.
  • [x] Follow through on deletion of all listed elements.
  • [x] Write a test, and list any tests that should be written.
• Might not show the list of descendant elements right now, but definitely confirm deletion before following through. Don't allow accidental one-click deletions of higher level elements with many descendants!

[ehmatthes]

See this post about getting all items that will be deleted.

[ehmatthes]

Use DeleteView?

[ehmatthes]

Support deletion of:

• [x] eus
• [x] cas
• [x] sdas
• [ ] sas
• [ ] orgs