Add functoolz.reorder_args

[groutr]

Candidate function to reorder arguments of an existing function.
Allows alternative function signatures that might be more useful to curry. The wrapped function name reflects the argument remapping for easier debugging.

[groutr]

Apparently the .replace method on code objects wasn't introduced till Python 3.8. Code objects have readonly attributes though, so I need to figure out a workaround for updating the wrapper function name.

[groutr]

@eriknw The test failures I think are caused by the linter. This is ready to look over though.

[ZeroBomb]

I have also reached for and missed a 'reorder' function, especially when dealing with some of the dicttoolz functionality like assoc (I don't always want the dictionary as the first arg). I'm not as big a fan of the two-argument approach here. I would prefer a single argument to designate the order, and there are a few ways to do that:

• you could supply a tuple indicating the position you want each argument to come from or go to, so you'd do something like

def reorder(f, ordering):
    def inner(*args, **kwargs):
        return f(*[args[i] for i in ordering], **kwargs)
   return inner   

• you could supply a dictionary defining the positional changes you want to make. This would free you from needing to specify the position of every argument, but would be a a little tricky to specify correctly if you had a lot of args. So you'd do something like this:

def reorder(f, ordering):
    # handle the case of incomplete specification by assuming flips, e.g. {2:1} requires a corresponding {1:2}
   complete_ordering = merge(dict(map(reverse, ordering.items())), ordering)

    def inner(*args, **kwargs):
        return f(*[args[get_in(complete_ordering, [i], default=i)] for i  in range(len(args))], **kwargs)
   return inner