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/InventoryScreen.cpp

@@ -31,8 +31,8 @@ void InventoryScreen::renderLabels()
 void InventoryScreen::render(int xm, int ym, float a)
 {
     AbstractContainerScreen::render(xm, ym, a);
-    this->xMouse = (float)xm;
-    this->yMouse = (float)ym;
+    this->xMouse = static_cast<float>(xm);
+    this->yMouse = static_cast<float>(ym);
 }
 
 void InventoryScreen::renderBg(float a)