Can generate invalid code for functions with vararg

[Michal Kwiatkowski]

When varargs is present, all preceding arguments should be positioned, not named. Currently test generator will generate invalid code for a function like foo:

>> def foo(a, *args):
... pass
>>> foo(a=4, *(1, 2, 3))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: foo() got multiple values for keyword argument 'a'
>>> foo(a=4, 1, 2, 3)
SyntaxError: non-keyword arg after keyword arg

pythoscope.generator.call_as_string doesn't yet support sorting arguments by position, so a bit of rework is needed there.

[Michal Kwiatkowski (ruby)]

Fixed in trunk r323.