runtime: re-prefix r5js.procspec private members
macro: make r5js.ListLikeTransformer.subtransformers private
parse+macro: introduce QuoteTransformer
macro: make r5js.ListListTransformer#couldMatch private
parse+macro: introduce r5js.VectorTransformer
parse+macro: introduce r5js.ListTransformer
parse+macro: introduce r5js.DottedListTransformer and make ListLikeTransformer private
macro: internal refactor of r5js.ListLikeTransformer_+subclasses to remove r5js.DatumType