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.World/ChunkSource.h

@@ -73,7 +73,7 @@ public:
 	virtual bool tick() = 0;
 	virtual bool shouldSave() = 0;
 
-	virtual LevelChunk **getCache() { return NULL; }		// 4J added
+	virtual LevelChunk **getCache() { return nullptr; }		// 4J added
 	virtual void dataReceived(int x, int z) {}				// 4J added
 
 	/**