Adds the "eval" function to Promise (see http://www.bluejava.com/4PQ for details)

Promise.eval

Promise.eval = function(ar)
{
	// We accept either an array or items specified as individual arguments...
	// ...but we convert the series into an array either way
	if(!Array.isArray(ar))
		ar = Array.prototype.slice.call(arguments)

	var items = { } // map names to items

	// This forEach is where it all happens - we evaluate each item within the eval array.
	// If there are dependencies, those are first resolved.
	// Its the mother of all promise workflows is just 10 lines!
	ar.forEach(function(zex, i) {
		items[zex.name || ("_p" + i)] =
			Promise.all((zex.deps || []).map(function(arg) {
						// even if items[arg] is undefined, using "arg in items" is true when the property exists
						if(typeof arg === "string" && arg in items)
							return items[arg]
						else
							return arg
					}))
				.then(function(dResults) {
						var value = zex.value
						if(typeof value === "function")
							value = value.apply(null, dResults)
						return value
					})
		})

	// Now we just wait for each promise to complete - then assign the resolved value to its named property
	var names = Object.keys(items),
		itemVals = names.map(function(name) { return items[name] }) // Object.values()

	return Promise.all(itemVals)
		.then(function(paResults) {
				var results = { }
				names.forEach(function(name, i) {
						results[name] = paResults[i]
					})
				return results
			})
}