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/MineShaftFeature.cpp

@@ -32,7 +32,7 @@ bool MineShaftFeature::isFeatureChunk(int x, int z, bool bIsSuperflat)
 {
 	bool forcePlacement = false;
 	LevelGenerationOptions *levelGenOptions = app.getLevelGenerationOptions();
-	if( levelGenOptions != NULL )
+	if( levelGenOptions != nullptr )
 	{
 		forcePlacement = levelGenOptions->isFeatureChunk(x,z,eFeature_Mineshaft);
 	}