extend BNF grammar and tokens with meta, quote, syntax-quote, unquote, and unquote-splicing
add new tokens to regexizer and test
get testhelper working with require and pass in to test modules to allow them to test for exceptions
fix tokenizer bug:  char-long action now saves line/col data; tokenize nil and booleans as symbols but separate in the symbol action
extend ast, parser, and ast_to_jstree to support new forms: syntaxquote, quote, unquote, metadata, unquotesplicing, and deref
unit tests for ast->jstree converter
refactor ast->jstree module to reduce code duplication
simplify table converter; don't have open state set for atoms