Support for promises

[jamesjwarren]

Would be nice to have a promise interface, instead of callbacks, so methods could be chained like:

var createUser = factory.create('user', { name: 'Bob' })
var createGroup = factory.create('group', { name: 'Group 1' })

createUser
  .then(function(user){
    return [user, createGroup];
  })
  .spread(function(user, group) {
     // do some testing
  });

[Lando-L]

+1