v0.8.0

Enhancements

• [Select] Most Document functions now raise if an unknown node_id is provided, when before they might have raised or might have handle the situation gracefully
• [Select] Add get_root_ids/1, get_node_ids/1, and fetch_node/2 to Document
• [Select] Add Document.delete_node/2, courtesy of @willbarrett
• [Readability] Remove Credo
• [Readability] Add .formatters.exs and mix format project

Fixes

• [All] Fix various typespecs