Bug:7723 and Skill Cooldowns

Fixed 7723, skill cooldowns are no longer have concurrent duplicates, when adding cooldown for a skill already in cooldown the timer is modified instead.
http://hercules.ws/board/tracker/issue-7723-skill-blockpc-end-error
Special Thanks to Haru, Wend and Beret.
Also fixed skill cooldown duration/total display for characters that relog with a skill cooldown on clients 20120604 or higher

Signed-off-by: shennetsind <ind@henn.et>
Merge branch 'master' of https://github.com/HerculesWS/Hercules