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/ReedsFeature.cpp

@@ -12,7 +12,7 @@ bool ReedsFeature::place(Level *level, Random *random, int x, int y, int z)
 		int z2 = z + random->nextInt(4) - random->nextInt(4);
 
 		// 4J Stu Added to stop reed features generating areas previously place by game rule generation
-		if(app.getLevelGenerationOptions() != NULL)
+		if(app.getLevelGenerationOptions() != nullptr)
 		{
 			LevelGenerationOptions *levelGenOptions = app.getLevelGenerationOptions();
 			bool intersects = levelGenOptions->checkIntersects(x2, y2, z2, x2, y2, z2);