was_called_with should treat named arguments as possible positional arguments

[tsande01]

e.g.

from pyne.test_doubles.expectations import expect
from pyne.pyne_test_collector import it
from pyne.pyne_tester import pyne
from pyne.test_doubles.spy import stub

@pyne
def _():
    @it("should match positional arguments when they are named explicitly")
    def _(self):
        class SomeClass():
            def some_method(self, arg1, arg2):
                pass

        instance = SomeClass()
        stub(instance, instance.some_method)
        instance.some_method("first-arg", arg2="second-arg")
        expect(instance.some_method).was_called_with(arg1="first-arg", arg2="second-arg")