assigned the owner of GameValueChangers to character prefabs
added owner change event for GameValue and GameValueChanger
removed OnGameValueChangerApplyChanger event
added OnObjectDealDamage event
added OnObjectDealHeal and OnObjectKills event
added UpdateSkill fucntion for SkillCaster
implementing powerups
refactoring on TargetFinders and TargetEffectAppliers, TargetEffectApplier now does not have dependency on TargetFinder, removed FinderPosition member in TargetFinder, implemented HealOwnerOnOwnerKills powerup
fixed typo compile error
finished implementing HealOnKill powerup and basic powerup script, added HealOnKill powerup prefabs, various refactoring
implemented reflect damage powerup, added reflect damage powerup prefabs
updated ShotGunSmoke and ReflectDamagePowerUp prefabs, removed useless folder
Merge branch 'develop' into JackySprint10

Conflicts:
	UnityProject/Assets/Resources/Prefabs/GameSetUp/MainCharacter.prefab
	UnityProject/Assets/Resources/Prefabs/GameSetUp/PrefabManager.prefab
	UnityProject/Assets/Scenes/GameStart.unity
	UnityProject/Assets/Scripts/Constants/GameScriptEventConstants.cs
	UnityProject/Assets/Scripts/Constants/PrefabConstants.cs
updated PrefabManager, updated ShotGunSmoke, fixed compile error
Merge pull request #76 from jackykschou/JackySprint10

Jacky sprint10