Skill cast delay animation related

[UTengine]

When you cast skills to a mob there is a delay in between there seems to be going something wrong I haven't been able to pinpoint it yet, casting a skill walking backwards you can cast another fine. Also when you casted the skill and the mob dies same delay goes for Z target, iscasting returns true even if the animation has ended which prevents us from casting the next skill and use Z target.

See: https://github.com/srmeier/KnightOnline/commit/6fd9d939f7c0b8e8ce689a78391766ec938ff1e1