Server/PacketIO: Added SMSG_CLEAR_COOLDOWNS opcode and structure.
Merge pull request #182 from Zangdar-O/opcode-cooldowns

Server/PacketIO: Added SMSG_CLEAR_COOLDOWNS opcode and structure.
Reverted changes by https://github.com/ProjectSkyfire/SkyFire_5xx/commit/cef781a9f602dcd512de6fdc9f96164f8c20e1f2
Will rewrite this. Fixes opening of vendors and trainers.

Signed-off-by: SkyFire <admin@projectskyfire.org>