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/DebugOptionsPacket.cpp

@@ -28,12 +28,12 @@ void DebugOptionsPacket::handle(PacketListener *listener)
 
 void DebugOptionsPacket::read(DataInputStream *dis) //throws IOException
 {
-	m_uiVal = (unsigned int)dis->readInt();
+	m_uiVal = static_cast<unsigned int>(dis->readInt());
 }
 
 void DebugOptionsPacket::write(DataOutputStream *dos) // throws IOException
 {
-	dos->writeInt((int)m_uiVal);
+	dos->writeInt(static_cast<int>(m_uiVal));
 }
 
 int DebugOptionsPacket::getEstimatedSize()