Support fuzzy argument match

[awestendorf]

Sometimes it's not necessary to test for all kwargs, just a few specific ones. This can be done now with expect(..).args(.., x=ignore()), but you need to do that for each named parameter. One of the following APIs might be better:

expect(..).args(.., **ignore())

or

expect(..).like(..)

Wouldn't have to re-use ignore in the first case, a new comparator could be introduced. If **ignore() is supported, *ignore() should be as well. That could all be very crazy, but not out of the question.

The second case is something I've thought about for awhile, where it would be a fuzzy match on *a, **k, such that only the first N values in the test case would be compared against *a, and only the named parameters of the test case would be compared against **k.