FPS Arena

A class tutorial with some new features:

- Added turret projectiles, each turret having a different fire rate and range.

- Added a crosshair

- Changed angle/position of the player weapon's muzzle, projectiles are now centered from the player's POV.

- Added a sprint functionality, which increases walking speed when the left shift key is pressed.

- Added gems that add to your score, reaching a score of 1000 unlocks the victory platform and lets you win.