Project modernization (#630)

* Fixed boats falling and a TP glitch #266

* Replaced every C-style cast with C++ ones

* Replaced every C-style cast with C++ ones

* Fixed boats falling and a TP glitch #266

* Updated NULL to nullptr and fixing some type issues

* Modernized and fixed a few bugs

- Replaced most instances of `NULL` with `nullptr`.
- Replaced most `shared_ptr(new ...)` with `make_shared`.
- Removed the `nullptr` macro as it was interfering with the actual nullptr keyword in some instances.

* Fixing more conflicts

* Replace int loops with size_t and start work on overrides

Minecraft.World/NearestAttackableTargetGoal.h

@@ -41,7 +41,7 @@ private:
 	weak_ptr<LivingEntity> target;
 
 public:
-	NearestAttackableTargetGoal(PathfinderMob *mob, const type_info& targetType, int randomInterval, bool mustSee, bool mustReach = false, EntitySelector *entitySelector = NULL);
+	NearestAttackableTargetGoal(PathfinderMob *mob, const type_info& targetType, int randomInterval, bool mustSee, bool mustReach = false, EntitySelector *entitySelector = nullptr);
 
 	virtual ~NearestAttackableTargetGoal();