Add call state transition for {"nil":null}
Add helper for making last argument a NIL one
Add helper for setting last arg to bool
Add bool argument transition
Add indirect argument (int) argument passing
Add helper for set last argument to int
Add transition for parsing direct int
Add transition for integer indirect args per yajl number callback
Add helper for setting last argument to string
Add transition for string arguments
Add missing break in new arg case
Fix return values