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/OptionsScreen.cpp

@@ -47,9 +47,9 @@ void OptionsScreen::init()
 void OptionsScreen::buttonClicked(Button *button)
 {
     if (!button->active) return;
-    if (button->id < 100 && (dynamic_cast<SmallButton *>(button) != NULL))
+    if (button->id < 100 && (dynamic_cast<SmallButton *>(button) != nullptr))
 	{
-        options->toggle(((SmallButton *) button)->getOption(), 1);
+        options->toggle(static_cast<SmallButton *>(button)->getOption(), 1);
         button->msg = options->getMessage(Options::Option::getItem(button->id));
     }
     if (button->id == VIDEO_BUTTON_ID)