[ticket/12809] Fix select button and dropdown list items in RTL.

PHPBB3-12809
[ticket/12809] Remove obsolete rules and selector.

PHPBB3-12809
[ticket/12809] Restore text-align for the pagination.

PHPBB3-12809
Merge branch 'ticket/12809' of https://github.com/prototech/phpbb into prototech-ticket/12809

Conflicts:
	phpBB/styles/prosilver/theme/responsive.css