Added immediate concerns to todo
Fix some deep problems with path literals in code
Major refactoring of parser to allow nodes to perform static analysis / type checking for themselves as an error-checking pass, and general cleanups / rearranged responsibilities
More major refactoring of Nodes and their setup and responsibilities.
Final refactorings to fix some critical parsing bugs.  "setup" is the new "complete" for Nodes.
Improve error handling between parser and evaluator
Cleanups regarding unimplemented Type
Add TODO to explain why the parser can get stuck
Allow code and expression blocks to execute
Add skeleton of Global scope.  Refactor AST and RootNode to be much cleaner: we just re-use the RootNode as a bare member of AST, use less pointers.
To implement Global, give every Node a pointer to the root.  Kind of ugly but fine for now.  Allow nodes to analyze themselves down(parnt-first) or up (children-first).