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/LavaSlime.cpp

@@ -55,7 +55,7 @@ ePARTICLE_TYPE LavaSlime::getParticleName()
 
 shared_ptr<Slime> LavaSlime::createChild()
 {
-	return shared_ptr<LavaSlime>( new LavaSlime(level) );
+	return std::make_shared<LavaSlime>(level);
 }
 
 int LavaSlime::getDeathLoot()