[s1860] Creature respawn position, use m_respawnPos as general respawn Position also for Creatures from DB. Now we can change Respawn Points in Script. Good for EscortAI and some Boss Scripts.

Note: SetSummonPoint is renamed to SetRespawnPoint. Didn't found any use of it in ScriptDev2 but if any please update script.

(based on commit [12322] - 6d8ff03)