Modernize project codebase (#906)

* 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

* Add safety checks and fix a issue with vector going OOR

Minecraft.World/OfferFlowerGoal.cpp

@@ -17,12 +17,12 @@ bool OfferFlowerGoal::canUse()
 	if (!golem->level->isDay()) return false;
 	if (golem->getRandom()->nextInt(8000) != 0) return false;
 	villager = weak_ptr<Villager>(dynamic_pointer_cast<Villager>( golem->level->getClosestEntityOfClass(typeid(Villager), golem->bb->grow(6, 2, 6), golem->shared_from_this()) ));
-	return villager.lock() != NULL;
+	return villager.lock() != nullptr;
 }
 
 bool OfferFlowerGoal::canContinueToUse()
 {
-	return _tick > 0 && villager.lock() != NULL;
+	return _tick > 0 && villager.lock() != nullptr;
 }
 
 void OfferFlowerGoal::start()