initial PEG.js grammar
update project with pegjs and supervisor
remove old parser (will defer to PEG-generated parser)
implement scalars in jd grammer
implement basic tuples in peg grammar
revise :as rule; support :as in tuples
revise sequence handling
support tuple rest clause (scalar only at the moment)
support assoc w/ binding pairs in grammar
support :as clause and sequenced assoc
fix spacing
support keyed assocs in grammar
remove comment
simplify tuple rule (by prefixing expr with s*)
extract methods extend_seq and extend_as
fix indentation
enable all tests except sym duplication; modify a couple tests to demonstrate optional whitespace
permit optional whitespace
check for duplicated symbols
add semicolon to end of statement