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/system.cpp

@@ -64,7 +64,7 @@ int64_t System::nanoTime()
 
 	// Using double to avoid 64-bit overflow during multiplication for long uptime
 	// Precision is sufficient for ~100 days of uptime.
-	return (int64_t)((double)counter.QuadPart * 1000000000.0 / (double)s_frequency.QuadPart);
+	return static_cast<int64_t>(static_cast<double>(counter.QuadPart) * 1000000000.0 / static_cast<double>(s_frequency.QuadPart));
 #else
 	return GetTickCount() * 1000000LL;
 #endif