WordPress Next & Prevous Page not Post with Bootstrap pager styling

NextPrevious Pages function NOT posts

<!-- add this code in page.php to display Next page and Previous page link below pages in WordPress
this will display next and previous page link not next previous post link
http://codex.wordpress.org/Next_and_Previous_Links#The_Next_and_Previous_Pages -->

<?php
	$pagelist = get_pages('sort_column=menu_order&sort_order=asc');
	$pages = array();
	foreach ($pagelist as $page) {
	   $pages[] += $page->ID;
	}

	$current = array_search(get_the_ID(), $pages);
	$prevID = $pages[$current-1];
	$nextID = $pages[$current+1];
?>

<ul class="pager">
	<?php if (!empty($prevID)) { ?>
		<li class="previous">
		<a href="<?php echo get_permalink($prevID); ?>"
		  title="<?php echo get_the_title($prevID); ?>">Previous Page</a>
		</li>
	<?php }
if (!empty($nextID)) { ?>
		<li class="next">
			<a href="<?php echo get_permalink($nextID); ?>" 
		 title="<?php echo get_the_title($nextID); ?>">Next Page</a>
		</li>
	<?php } ?>
</ul><!-- .navigation -->

If you want to display title of next and previous instead of PREVIOUS PAGE and NEXT PAGE use this code

<ul class="pager">
        <?php if (!empty($prevID)) { ?>
            <li class="previous">
            <a href="<?php echo get_permalink($prevID); ?>"
              title="<?php echo get_the_title($prevID); ?>"><?php echo get_the_title($prevID); ?></a>
            </li>
        <?php }
    if (!empty($nextID)) { ?>
            <li class="next">
                <a href="<?php echo get_permalink($nextID); ?>" 
             title="<?php echo get_the_title($nextID); ?>"><?php echo get_the_title($nextID); ?></a>
            </li>
        <?php } ?>
    </ul><!-- .navigation -->