Inherit all methods of object (including "constructor"), but modify some of them
<p>Let's imagine that we have object Animal</p>

<pre><code>$.Animal = function(options) {
  this.defaults  = { name : null }
  this.options   = $.extend(this.defaults, options);
}

$.Animal.prototype.saySomething = function() {
  alert("I'm animal!");
}
</code></pre>

<p>Now I'd like to create Cat object. It is absolutely similar to $.Annimal, but method saySomething() will look like this one...</p>

<pre><code>$.Cat.prototype.saySomething = function() {
  alert("I'm cat!");
}
</code></pre>

<p>How can I inherit from Animal to create new object Cat and redefine saySomething() method?</p>

<p>Thank you.</p>
