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/Gui.h

@@ -59,7 +59,7 @@ public:
 	void displayClientMessage(int messageId, int iPad);
 
 	// 4J Added
-	DWORD getMessagesCount(int iPad) { return (int)guiMessages[iPad].size(); }
+	DWORD getMessagesCount(int iPad) { return static_cast<int>(guiMessages[iPad].size()); }
 	wstring getMessage(int iPad, DWORD index) { return guiMessages[iPad].at(index).string; }
 	float getOpacity(int iPad, DWORD index);