Game server/skill system: crudely implemented mage skill "Blink". Need to revise to use client-calculated orientation for greater accuracy. Resolves #150.
Game server/skill system: implemented "Vampiric Fire" as per 1.8xx (it ignores mobs). Resolves #149.
Game server/skill system: GrantType4Buff() & RemoveType4Buff() are no longer specific to players.
Game server/skill system: if instant cast is enabled, it will now be unset after the following skill has been cast. Resolves #148.