Core/Script: OnQuestAccept() it's triggered by Player::AddQuest() now.

Small description:
This patch repair the situation where quest got auto-complete flag then creaturescript(c++ one) OnQuestAccept() it's skipped.
- the same situation is for quest-chains if next quest got auto-complete then OnQuestAccept() it's skipped.
- Also include quests where source is gameobject.