New .construct(args) function for stamps.

Creates object and passes given variables to each closure. Enables following syntax:
```JS
var stamp = stampit.enclose(function constructor(nick, generation) {
  var name = nick,
    surname = generation;
  this.getFullName = function getFullName() {
    return name + ' ' + surname;
  };
});

var transformer = stamp.construct('Optimus', 'Prime');
console.log(transformer.getFullName()); // outputs: Optimus Prime
```

Browserify did something different to the original source. I hope it's okay.

Also I have added a test for the function.