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/GhastModel.cpp

@@ -23,7 +23,7 @@ GhastModel::GhastModel() : Model()
 
         tentacles[i]->x = xo;
         tentacles[i]->z = yo;
-        tentacles[i]->y = (float)(31 + yoffs);
+        tentacles[i]->y = static_cast<float>(31 + yoffs);
     }
 
 	// 4J added - compile now to avoid random performance hit first time cubes are rendered