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/BlockReplacements.cpp

@@ -8,8 +8,8 @@ void BlockReplacements::staticCtor()
 {
     for (int i = 0; i < 256; i++)
 	{
-        byte b = (byte) i;
-        if (b != 0 && Tile::tiles[b & 0xff] == NULL)
+        byte b = static_cast<byte>(i);
+        if (b != 0 && Tile::tiles[b & 0xff] == nullptr)
 		{
             b = 0;
         }