hash idea

``` js
var coreduction = require("coreduction/hash")

var r1 = reducible()
var r2 = reducible()
var r3 = reducible()

var r = coreduction({
1: r1
, 2: r2
, 3: r3
})

fold(r, function (hash) {
/* hash[1], hash[2], hash[3] */
})
```

The idea here is very similar to [execute](https://github.com/colingo/execute#example) take an arbitrary hash of reducibles and coreduct them together using an assembler function that builds a hash using the supplied keys.

This is way better then coreduction returning tuples or triples as they are a pain to unpack