Completed UI in gamescene

Added buttons and labels in game scene
Created code connections for each button and label
Created ship and asteroid .ccb files with physics enabled
Created Xcode files for both ship and asteroid
Completed immediately preceding push
Working ship

Implemented ship rotation buttons
Implemented boost
Shooting implemented

Added bullet.ccb in sprite builder
Implemented method to shoot bullets from the ship
Asteroid implementation

Implemented asteroid class
Overwrote the update function for asteroid
Perfected collision handling

Added bullet class in Xcode
Made empty functions that handle collisions between asteroids and
bullets, and asteroids and ships
Bullet asteroid collisions fully implemented

Added implementation for bullet asteroid collisions
Enabled multitouch in the game scene
Merge branch 'Gameplay-Round-2'
Pre-merge commit
Merge branch 'Gameplay-Round-2'