I'm terribly sorry…

fixes a bug caused by my previous PR (#24) and hardcoded generation of `getvars` variable.
bug description: when `disable_link_for_first_page` is true, for first page's link there was no replacing of "&" to "?" for first GET parameter, so there was 404.
i didn't rewrote `getvars` generation, thus i avoid increasing of complexity. i'll rewrote it later, if i'll be allowed to do so.