[ticket/12613] Improved pagination

PHPBB3-12613
[ticket/12613] Fix dropdown-up positioning

PHPBB3-12613
[ticket/12613] Fix tests

PHPBB3-12613
[ticket/12613] Removed all previous_page / next_page text links

PHPBB3-12613
[ticket/12613] Removed jump-to placeholder and added .focus() check

PHPBB3-12613
[ticket/12613] Fix functional test and post sorting bug

PHPBB3-12613
[ticket/12613] Removed form in order to prevent nested forms

PHPBB3-12613
[ticket/12613] Renamed jump-to to page-jump to prevent confusion

Jump-to can easily be confused with forum-jump.
Also switched the lang vars to reflect changes better

PHPBB3-12613
[ticket/12613] Dropdown-visible page-jump icon, fix focus() timing

Also removed outdated CSS

PHPBB3-12613
[ticket/12613] Minor CSS fixes

PHPBB3-12613
[ticket/12613] Pagination should never be in responsive linklist

PHPBB3-12613
[ticket/12613] Minor $bull; and <hr> fix

PHPBB3-12613
[ticket/12613] Fixes from comments (single quotes and typos)

PHPBB3-12613
[ticket/12613] Don't display page-jump if all pages are visible (6)

PHPBB3-12613