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/FleeSunGoal.cpp

@@ -18,10 +18,10 @@ bool FleeSunGoal::canUse()
 {
 	if (!level->isDay()) return false;
 	if (!mob->isOnFire()) return false;
-	if (!level->canSeeSky(Mth::floor(mob->x), (int) mob->bb->y0, Mth::floor(mob->z))) return false;
+	if (!level->canSeeSky(Mth::floor(mob->x), static_cast<int>(mob->bb->y0), Mth::floor(mob->z))) return false;
 
 	Vec3 *pos = getHidePos();
-	if (pos == NULL) return false;
+	if (pos == nullptr) return false;
 	wantedX = pos->x;
 	wantedY = pos->y;
 	wantedZ = pos->z;
@@ -48,5 +48,5 @@ Vec3 *FleeSunGoal::getHidePos()
 		int zt = Mth::floor(mob->z + random->nextInt(20) - 10);
 		if (!level->canSeeSky(xt, yt, zt) && mob->getWalkTargetValue(xt, yt, zt) < 0) return Vec3::newTemp(xt, yt, zt);
 	}
-	return NULL;
+	return nullptr;
 }