Add method to wrap functions (promiserize)

[amatiasq]

We need a function to wrap any function so the execution is deferred until all promise-arguments are fulfilled. So this code

getNumber(function(num) {
    var result = Math.pow(num);
    heavyCheck(result, function(isValid) {
        console.log("Valid:", isValid);
    });
});

Can be written like this:

heavyCheck = promiserize(heavyCheck);
console.log = promiserize(console.log);

var result = getNumber();
var isValid = heavyCheck(result);
console.log(isValid);

result is a promise
isValid is a promise
heavyCheck will wait until result is fulfilled then will perfom it's async operation and will return a promise
isValid will be binded to this promise so when the returned promise is resolved or rejected isValid will be too.
console.log will wait until isValid is fulfilled