TutorialScene features + Some GameScene Features

Added Completed Tutorial including:

1. Feat; Dog Interaction
2. Feat; Gun Handling
3. Feat; Zombie Shooting
4. Feat; Next game scene loading

Added Game Scene Features including:

1. Feat; Countdown Timers
2. Tweak; Zombie Spawning Settings - Movement Speed, Spawn Rate
3. Tweak; Scoring System Adjusted - Zombies subtract score when attacking