custom metabox is not saving LINK value when updated

<?php
add_action( 'init', 'codex_team_init' );
function codex_team_init() {
	$labels = array(
		'name'               => _x( 'team', 'post type general name', 'your-plugin-textdomain' ),
		'singular_name'      => _x( 'teams', 'post type singular name', 'your-plugin-textdomain' ),
		'menu_name'          => _x( 'Team', 'admin menu', 'your-plugin-textdomain' ),
		'name_admin_bar'     => _x( 'team', 'add new on admin bar', 'your-plugin-textdomain' ),
		'add_new'            => _x( 'Add New', 'team', 'your-plugin-textdomain' ),
		'add_new_item'       => __( 'Add New team', 'your-plugin-textdomain' ),
		'new_item'           => __( 'New team', 'your-plugin-textdomain' ),
		'edit_item'          => __( 'Edit team', 'your-plugin-textdomain' ),
		'view_item'          => __( 'View team', 'your-plugin-textdomain' ),
		'all_items'          => __( 'All team', 'your-plugin-textdomain' ),
		'search_items'       => __( 'Search team', 'your-plugin-textdomain' ),
		'parent_item_colon'  => __( 'Parent team:', 'your-plugin-textdomain' ),
		'not_found'          => __( 'No team found.', 'your-plugin-textdomain' ),
		'not_found_in_trash' => __( 'No team found in Trash.', 'your-plugin-textdomain' )
	);

	$args = array(
		'labels'             => $labels,
		'public'             => true,
		'publicly_queryable' => true,
		'show_ui'            => true,
		'show_in_menu'       => true,
		'query_var'          => true,
		'rewrite'            => array( 'slug' => 'team' ),
		 'supports'            => array( 'title', 'editor','page-attributes','thumbnail' ),
		'capability_type'    => 'post',
		'has_archive'        => true,
		'hierarchical'       => false,
		'menu_position'      => null,
		'menu_icon' => get_bloginfo('template_directory') . '/img/icon4.png'
	);

	register_post_type( 'team', $args );
}

$prefix = 'mmc_';
$post_types = array('post', 'page');
//set up the box and teh fields inside
$meta_box = array(
	'id' => 'meta-box',
	'title' => 'Social Icon', //title of box

	'context' => 'side', //normal, advanced or side
	'priority' => 'default',
	'fields' => array(  //and now for the custom fields in the box

		array(
			'name' => 'Icon',
			'id' => $prefix . 'icon',
			'type' => 'select',
			'options' => array('fa-google' => 'google',
								'fa-facebook' => 'facebook',
								'fa-skype' => 'skype',
								'fa-twitter' => 'twitter',
								'fa-yahoo' => 'yahoo',
								'fa-youtube' => 'youtube',
								)
		)
	)
);

add_action('admin_menu', 'theme_add_box');

// Add meta box
function theme_add_box() {
	global $meta_box;
	global $post_types;

	foreach($post_types as $type){
		//(id, title, callback, post type, context, priority, callback args)
		add_meta_box($meta_box['id'], $meta_box['title'], 'social_meta_box', $type='team', $meta_box['context'], $meta_box['priority']);
	}
}
function social_meta_box() {
	global $meta_box, $post;

	// Use nonce for verification
	echo '<input type="hidden" name="theme_meta_box_nonce" value="', wp_create_nonce(basename(__FILE__)), '" />';

	echo '<table class="form-table">';

	foreach ($meta_box['fields'] as $field) {
		// get current post meta data
		$meta = get_post_meta($post->ID, $field['id'], true);
        $title = get_post_meta($post->ID, '_title', true);
echo '<tr>',
				'<th style="width:20%"><label for="', $field['id'], '">', $field['name'], '</label></th>',
				'<td>';
		switch ($field['type']) {
			case 'text':
				echo '<input type="text" name="', $field['id'], '" id="', $field['id'], '" value="', $meta ? $meta : $field['std'], '" size="30" style="width:97%" />',
					'<br />', $field['desc'];
				break;
			case 'textarea':
				echo '<textarea name="', $field['id'], '" id="', $field['id'], '" cols="60" rows="4" style="width:97%">', $meta ? $meta : $field['std'], '</textarea>',
					'<br />', $field['desc'];
				break;
			case 'select':
				echo '<select name="', $field['id'], '" id="', $field['id'], '">';
				foreach ($field['options'] as $value => $name) {
					echo '<option value="'.$value.'" ';
					echo $meta == $value ? ' selected="selected"' : '', '>', $name, '</option>';
				}
				echo '</select>';
				break;
			case 'radio':
				foreach ($field['options'] as $option) {
					echo '<input type="radio" name="', $field['id'], '" value="', $option['value'], '"', $meta == $option['value'] ? ' checked="checked"' : '', ' />', $option['name'];
				}
				break;
			case 'checkbox':
				echo '<input type="checkbox" name="', $field['id'], '" id="', $field['id'], '"', $meta ? ' checked="checked"' : '', ' />';
				break;
		}
		echo 	'</tr><tr><td>';
		echo '<i class="fa fa-2x '.$meta.'"></i>';
		echo	'Link:</td><td><input type="text" name="_title" value="' . $title  . '" class="widefat"></td></tr>';
	}

	echo '</table>';
}
add_action('save_post', 'theme_save_data');
function theme_save_data($post_id) {
	global $meta_box;

	// verify nonce
	if (!wp_verify_nonce($_POST['theme_meta_box_nonce'], basename(__FILE__))) {
		return $post_id;
	}

	// check autosave
	if (defined('DOING_AUTOSAVE') && DOING_AUTOSAVE) {
		return $post_id;
	}

	// check permissions
	if ('page' == $_POST['post_type']) {
		if (!current_user_can('edit_page', $post_id)) {
			return $post_id;
		}
	} elseif (!current_user_can('edit_post', $post_id)) {
		return $post_id;
	}

	foreach ($meta_box['fields'] as $field) {
		$old = get_post_meta($post_id, $field['id'], true);
		$new = $_POST[$field['id']];

		if ($new && $new != $old) {
			update_post_meta($post_id, $field['id'], $new);
		} elseif ('' == $new && $old) {
			delete_post_meta($post_id, $field['id'], $old);
		}
	}
	$events_meta['_title'] = $_POST['_title'];
	foreach ($events_meta as $key => $value) { // Cycle through the $events_meta array!
		if( $post->post_type == 'revision' ) return; // Don't store custom data twice
		$value = implode(',', (array)$value); // If $value is an array, make it a CSV (unlikely)
		if(get_post_meta($post->ID, $key, FALSE)) { // If the custom field already has a value
			update_post_meta($post->ID, $key, $value);
		} else { // If the custom field doesn't have a value
			add_post_meta($post->ID, $key, $value);
		}
		if(!$value) delete_post_meta($post->ID, $key); // Delete if blank
	}
}
$events_meta['_title'] = $_POST['_title'];
function social_style(){
	$style_url = plugins_url('css/font-awesome.css', __FILE__);
	wp_enqueue_style( 'fontawesome', $style_url );
	?>

<?php
}
add_action('wp_enqueue_scripts','social_style');
add_action('admin_enqueue_scripts','social_style');

//theme template tag
function social_icon(){
	global $prefix;
	global $post;
	$icon = get_post_meta($post->ID, $prefix.'icon', true);
     $link=get_post_meta($post->ID, '_title', true);
	if($icon && $link != ''): ?>
		<a href="<?php echo $link; ?> " class="fa <?php echo $icon; ?> mmc-fontawesome-meta-icon"></a>
	<?php endif;
}
?>