Implement Rune Grace Period mechanic

Signed-off-by: Morgoporc <j.fraisse45@laposte.net>

Fix typo

Signed-off-by: Morgoporc <j.fraisse45@laposte.net>

Add crashfix to Rune Grace Period

Signed-off-by: Morgoporc <j.fraisse45@laposte.net>
Merge branch 'master' of github.com:Morgoporc/TrinityCore