Modernize project codebase (#906)

* 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

* Add safety checks and fix a issue with vector going OOR

Minecraft.World/TextureChangePacket.cpp

@@ -24,7 +24,7 @@ TextureChangePacket::TextureChangePacket(shared_ptr<Entity> e, ETextureChangeTyp
 void TextureChangePacket::read(DataInputStream *dis) //throws IOException 
 {
 	id = dis->readInt();
-	action = (ETextureChangeType)dis->readByte();
+	action = static_cast<ETextureChangeType>(dis->readByte());
 	path = dis->readUTF();
 }
 
@@ -42,5 +42,5 @@ void TextureChangePacket::handle(PacketListener *listener)
 
 int TextureChangePacket::getEstimatedSize() 
 {
-	return 5 + (int)path.size();
+	return 5 + static_cast<int>(path.size());
 }