[np] Use bnumber not number for number node
[np] First steps towards AST generator
[np] Auto-export node types
[np] AST DSL BBQ
[np] Fix simple_exp to be more generic
[np] AST for empty array
[np] Array AST
[np] Add AST tests
[np] AST for empty file
[np] Number literal for number AST
[np] Fix array AST
[np] Move brat-parser to ast.brat
[np] Basic hash table literals
[np] Regex
[np] Simple strings