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/SetHealthPacket.cpp

@@ -32,7 +32,7 @@ void SetHealthPacket::read(DataInputStream *dis) //throws IOException
 	saturation = dis->readFloat();
 	//        exhaustion = dis.readFloat();
 
-	damageSource = (ETelemetryChallenges)dis->readByte();
+	damageSource = static_cast<ETelemetryChallenges>(dis->readByte());
 }
 
 void SetHealthPacket::write(DataOutputStream *dos) //throws IOException