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/DefaultRenderer.h

@@ -5,5 +5,5 @@ class DefaultRenderer : public EntityRenderer
 {
 public:
 	virtual void render(shared_ptr<Entity> entity, double x, double y, double z, float rot, float a);
-	virtual ResourceLocation *getTextureLocation(shared_ptr<Entity> mob) { return NULL; };
+	virtual ResourceLocation *getTextureLocation(shared_ptr<Entity> mob) { return nullptr; };
 };