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/ThrownExpBottle.cpp

@@ -40,14 +40,14 @@ void ThrownExpBottle::onHit(HitResult *res)
 
 	if (!level->isClientSide)
 	{
-		level->levelEvent(LevelEvent::PARTICLES_POTION_SPLASH, (int) Math::round(x), (int) Math::round(y), (int) Math::round(z), 0);
+		level->levelEvent(LevelEvent::PARTICLES_POTION_SPLASH, static_cast<int>(Math::round(x)), static_cast<int>(Math::round(y)), static_cast<int>(Math::round(z)), 0);
 
 		int xpCount = 3 + level->random->nextInt(5) + level->random->nextInt(5);
 		while (xpCount > 0)
 		{
 			int newCount = ExperienceOrb::getExperienceValue(xpCount);
 			xpCount -= newCount;
-			level->addEntity(shared_ptr<ExperienceOrb>( new ExperienceOrb(level, x, y, z, newCount) ) );
+			level->addEntity(std::make_shared<ExperienceOrb>(level, x, y, z, newCount));
 		}
 
 		remove();