Layout and trivia

[Virtlink]

Implement layout and trivia that can optionally be ignored in the red view of the green tree.

Note: Annotations will not contain trivia, or if they do, there is no special support for filtering them.

• Add Trivia term type.
• Add new property to red terms that shows the subterms including trivia.
• Change getChildren of the red terms to only show the non-trivia terms.
• Ensure the number of non-trivia terms matches the arity of the constructor.
• Fix NameAgePair, it has to use dynamic indices (because there may be arbitrary trivia in the subterms).
• Write example for traversing trivia.
• Write example for inserting/removing trivia.
• Write example to show how trivia helps reconstructing the original source.
• Write test for children with trivia.