added OnGameValueChangerApplyChange event, refactored GameValue and GameValueChanager
fixed where SingleRayCasterFinder always cast on the same position if a target is found, refactoring
updated shotGun smoke and trail prefab, updated prefabManager
add a GameValueChanger parameter to pass in the event OnGameValueCurrentValueChanged
updated enemy prefabs, added more powerup placeholders
OnObjectTakeDamager and OnObjectTakeHeal also takes in a gameValueChanger
fixed bug where event is triggered when GameValueChanger is deactive
Merge pull request #71 from jackykschou/SurvivalMode

Survival mode
added Owner field to GameValue and GameValueChanger
Merge branch 'develop' into JackySprint10

Conflicts:
	UnityProject/Assets/Resources/Prefabs/GameSetUp/PrefabManager.prefab
Merge pull request #70 from jackykschou/JackySprint10

Jacky sprint10
Merge pull request #72 from jackykschou/SurvivalMode

Added optional parameter for despawn time
Merge branch 'develop' into SurvivalMode