A more python-style list.sort. And keyword arguments.

    This implements a better (more python-style) list.sort.
    
    It's not really about that, though; it's about me figuring out a sane
    way forward for keyword-argument functions (and function
    metadata). But it's useful as is, and shouldn't break any existing
    code, so here you have it; I'm going to park it in my mind for a bit
    while sorting out the rest of the dict branch.