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/SlimeRenderer.cpp

@@ -41,7 +41,7 @@ void SlimeRenderer::scale(shared_ptr<LivingEntity> _slime, float a)
 	// 4J - dynamic cast required because we aren't using templates/generics in our version
 	shared_ptr<Slime> slime = dynamic_pointer_cast<Slime>(_slime);
 
-    float size = (float) slime->getSize();
+    float size = static_cast<float>(slime->getSize());
     float ss = (slime->oSquish + (slime->squish - slime->oSquish) * a) / (size * 0.5f + 1);
     float w = 1 / (ss + 1);
     glScalef(w * size, 1 / w * size, w * size);