* Arsenal top for first time since February 2014 * Headers from Giroud and Koscielny seal win over Everton * Mourinho sent from dugout as 10-man Chelsea lose again * West Ham up to third after derby victory over champions By Mike Collett LONDON, Oct 24 (Reuters) – Bitter rivals Arsene Wenger and Jose Mourinho had wildly contrasting afternoons on Saturday as Arsenal went top of the Premier League and champions Chelsea lost again with their …