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/BufferedImage.h

@@ -7,7 +7,7 @@ class DLCPack;
 class BufferedImage
 {
 private:
-	int *data[10];	// Arrays for mipmaps - NULL if not used
+	int *data[10];	// Arrays for mipmaps - nullptr if not used
 	int width;
 	int height;
 	void ByteFlip4(unsigned int &data);	// 4J added