remove quote '\'' parse form
Toward real-world usability...
vastlly increase number of builtin functions, plumb them into eval_test
allow NULL to be passed to environ_lookup to just determine if key is defined in environ
add 'defined?' functionality
add eval_err canary function
add better enter/exit tracing
make eval_norec default eval
add new too-few-args error message
add specific node value types -- value_t, u_value_t
add basic list of tests to be used later for automated validation