Core/Misc: Fix some static analysis issues

Fix some static analysis issues about missing NULL checks.
Pass safe Creature pointer instead of summoning a Creature, passing the GUID and retrieve the same Creature from GUID.
Core/Chat: Fix ChatFlood.MessageCount not being handled correctly

Fix Anti-flood chat system to always allow 1 more message than the count specified in the ChatFlood.MessageCount config parameter.
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore into ghbb
Core/SmartAI: Fix SMART_ACTION_ALLOW_COMBAT_MOVEMENT
Core/SmartScript: Allow flag to be added to spell to determine combat movement.
Greatly simplifies SAI combat scripting.
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore into ghbb
Scripting/Sholazar Basin: Fix warning
Merge branch 'master' of https://github.com/TrinityCore/TrinityCore into ghbb