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/NbtIo.cpp

@@ -52,11 +52,11 @@ CompoundTag *NbtIo::read(DataInput *dis)
 {
 	Tag *tag = Tag::readNamedTag(dis);
 
-	if( tag->getId() == Tag::TAG_Compound ) return (CompoundTag *)tag;
+	if( tag->getId() == Tag::TAG_Compound ) return static_cast<CompoundTag *>(tag);
 
-	if(tag!=NULL) delete tag;
+	if(tag!=nullptr) delete tag;
 	// Root tag must be a named compound tag
-	return NULL;
+	return nullptr;
 }
 
 void NbtIo::write(CompoundTag *tag, DataOutput *dos)