Update TODO list.
Correctly set the parent from AST pointers.
Tidy up doc comment.
Turn some commented out internal consistency checks into asserts.
Add ASCII file input wrapper.
Doc comment cleanup.
Allow rules to be constructed from character expressions
Constify rules.
Cleaned up dereferencing operators in ASTPtr.
Updated Calculator example to work with new APIs.
Remove remaining non-functional examples.
They can be resurrected later if required.
Finish the rename to pegmatite (missed all-uppercase macro).
Fix get_as<>() for the case where the receiver is null.
Lots more words in the readme.
Move the README to the top level.