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/PistonExtensionTile.cpp

@@ -7,7 +7,7 @@
 PistonExtensionTile::PistonExtensionTile(int id) : Tile(id, Material::piston,isSolidRender() )
 {
 	// 4J added initialiser
-	overrideTopTexture = NULL;
+	overrideTopTexture = nullptr;
 
 	setSoundType(SOUND_STONE);
 	setDestroyTime(0.5f);
@@ -20,7 +20,7 @@ void PistonExtensionTile::setOverrideTopTexture(Icon *overrideTopTexture)
 
 void PistonExtensionTile::clearOverrideTopTexture()
 {
-	this->overrideTopTexture = NULL;
+	this->overrideTopTexture = nullptr;
 }
 
 void PistonExtensionTile::playerWillDestroy(Level *level, int x, int y, int z, int data, shared_ptr<Player> player)
@@ -65,7 +65,7 @@ Icon *PistonExtensionTile::getTexture(int face, int data)
 
 	if (face == facing)
 	{
-		if (overrideTopTexture != NULL)
+		if (overrideTopTexture != nullptr)
 		{
 			return overrideTopTexture;
 		}