 Returns the first element of the array, undefined if the array is empty.
 
 <code><pre>
-  ["first", "second", "third"].first()
+   ["first", "second", "third"].first()
 => "first"
 </pre></code>
 

If length is not given return the element at start, again assuming the array 
is a circle.

@name wrap
@methodOf Array#


Returns an object containing the extremes of this array.

<code><pre>
   [-1, 3, 0].extremes()
=> {min: -1, max: 3}
</pre></code>

