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/LeashKnotRenderer.cpp

@@ -19,7 +19,7 @@ void LeashKnotRenderer::render(shared_ptr<Entity> entity, double x, double y, do
     glPushMatrix();
     glDisable(GL_CULL_FACE);
 
-    glTranslatef((float) x, (float) y, (float) z);
+    glTranslatef(static_cast<float>(x), static_cast<float>(y), static_cast<float>(z));
 
     float scale = 1 / 16.0f;
     glEnable(GL_RESCALE_NORMAL);