AI server: Removed references to the skill types not being used (for clarity).
AI server: Removed more unused methods for clarity.
AI server: It appears type 1 & 2 aren't used either (for users), which leaves only type 3 skills to be handled by this class.
AI server: Cleaned up CNpcMagicProcess::MagicPacket() & its callers to avoid constructing & parsing a packet every call.