Add custom href for links

[ilya-il]

Add custom href for links. To support POST-form pagination you should write JS function.

pagination = Pagination(page=page,
per_page=per_page,
total=total,
href='javascript:change_page({0})')

JS function will change page and submit form. Example from flask template:

<script type="text/javascript">
    function change_page ( page_num )
    {
      document.searchform.current_page.value = page_num ;
      document.searchform.submit() ;
    }
</script>