Fix bug reported by Ka-Ping Yee: The compiler botched parsing function

Fix bug reported by Ka-Ping Yee: The compiler botched parsing function
parameters that contained both anonymous tuples and *arg or **arg. Ex:
def f(a, (b, c), *d): pass

Fix the symtable_params() to generate names in the right order for
co_varnames slot of code object.  Consider *arg and **arg before the
"complex" names introduced by anonymous tuples.