Huge refactor to collision detection and rendering!

Main stuff: - I made a big refactor to collision detection that increased performance by a lot (at least for me) + made many monsters collision a lot more accurate. - In addition, I made the collision detection while on mounts more accurate. - Also optimized rendering. - Added 'Brutality' mechanism - special points you gain while having a "multi kill" title in the corner. Its not yet used, currently its just a counter in stats, but I have some plans with it. Anyway since I made a lot of changes to collision and rendering, please let me know if you encounter any new bugs as a result. Thanks! All changes: - Added one more level to 'Quality Food' powerup. - Made camera movement smoother. - Made Lava River slightly stronger. - Made Time Stop last a bit less. - Added optimizations in collision detection. - Optimized rendering static objects. - Added Brutality mechanism. - Improved collision accuracy when on big mount. - Improved some enemies collision shape. - Increased enemies melee multiplier over time.