Transform and Reduce argument order

[megawac]

See #892 for context

I am for async.reduce(arr, iteratee, [accumulator,] callback)

/cc @aearly @qsona @suguru03

[qsona]

I'm +1 for async.reduce(arr, iteratee, [accumulator,] callback). 💯

[suguru03]

+1
I agree. Thank you for notification!

[megawac]

I'm having second thoughts as I started writing test cases.

It's more logical I think to write

var arr = [....]

async.transform(arr, {}, function(memo, v, k) {
   memo[k] = v;
    cb();
}, function() {
    ....
}

then

var arr = [....]

async.transform(arr, function(memo, v, k) {
   memo[k] = v;
    cb();
}, {}, function() {
    ....
}

[aearly]

Yeah, the way it is now is easier to parse visually when you have an inline iteratee. I'm not sure what we should do here.

[megawac]

I think we should err on the side of no breaking changes honestly

[aearly]

Ok, then maybe we should keep the args ordering for transform and reduce as-is.