Minor changes to unit attack sound timings in collaboration with Bumbadadabum. Units sound timings changed: Assassin, Orcish Assassin, Orcish Slayer, Merman Warrior, Fencer, and Spearman ranged.

git-svn-id: http://svn.gna.org/svn/wesnoth/trunk@56559 75b3775d-3801-0410-9e12-e2e43121521d