Pagination problem with query vars

The pagination breaks when query variables are involved. For example, a search results page with just a search term paginates correctly, but a search for example.com/?s=ipsum&cat=3 becomes example.com/?s=ipsum&cat=3#038;cat=3&paged=2 in the pagination.

The problem is in the vantage_pagination() function: it uses a wrong base value for paginate_links():

echo paginate_links( array(
	'total' => $pages,
	'current' => $paged,
	'mid_size' => $showitems,
	'format' => ( $wp_rewrite->permalink_structure == '' || is_search() ) ? $format_query_string : $format_permalink,
	'base' => get_pagenum_link( false ) . '%_%',
) );

The fix is simple: you need to disable the escaping in get_pagenum_link() with get_pagenum_link( false, false ) – that way the URLs work.