Collection objects can act very much like arrays. This is especially evident in creating new
objects, or by converting Collection into an actual array:

{{{
$coll = new Collection();
$coll[] = 'foo';
// $coll[0] --> 'foo'

$coll = new Collection(array('data' => array('foo')));
// $coll[0] --> 'foo'

$array = $coll->to('array');
}}}

Apart from array-like data access, Collections allow for filtering and iteration methods:

{{{

$coll = new Collection(array('data' => array(0, 1, 2, 3, 4)));

$coll->first();   // 1 (the first non-empty value)
$coll->current(); // 0
$coll->next();    // 1
$coll->next();    // 2
$coll->next();    // 3
$coll->prev();    // 2
$coll->rewind();  // 0
}}}

The primary purpose of the `Collection` class is to enable simple, efficient access to groups
of similar objects, and to perform operations against these objects using anonymous functions.

The `map()` and `each()` methods allow you to perform operations against the entire set of values
in a `Collection`, while `find()` and `first()` allow you to search through values and pick out
one or more.

The `Collection` class also supports dispatching methods against a set of objects, if the method
is supported by all objects. For example: {{{
class Task {
	public function run($when) {
		// Do some work
	}
}

$data = array(
	new Task(array('task' => 'task 1')),
	new Task(array('task' => 'task 2')),
	new Task(array('task' => 'task 3'))
);
$tasks = new Collection(compact('data'));

// $result will contain an array, and each element will be the return
// value of a run() method call:
$result = $tasks->invoke('run', array('now'));

// Alternatively, the method can be called natively, with the same result:
$result = $tasks->run('now');
}}}