Adding support for class methods as well as closures.

Class methods can be passed as an array. You can use either instance or static methods. To use an instance method, consider the following:

    class TestClass
    	{
    		function test($page)
    		{
    			$page = str_replace("<div id=\"content\">", "<div id=\"content\"><p>Hello World!<br />This is a sample MyBB Plugin (which can be disabled!) that displays this message on all pages.</p>", $page);
    			return $page;
    		}
    	}

    	$obj = new TestClass();

    	$plugins->add_hook("pre_output_page", array($obj, 'test'));

 To use a static method, simply pass the class name as the first array parameter and the method name as the second.