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.Client/SpellParticle.cpp

@@ -13,7 +13,7 @@ SpellParticle::SpellParticle(Level *level, double x, double y, double z, double
 
 	size *= 0.75f;
 
-	lifetime = (int) (8 / (Math::random() * 0.8 + 0.2));
+	lifetime = static_cast<int>(8 / (Math::random() * 0.8 + 0.2));
 	noPhysics = false;
 
 	baseTex = 8 * 16;