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/MockedLevelStorage.cpp

@@ -9,7 +9,7 @@
 
 LevelData *MockedLevelStorage::prepareLevel() 
 {
-    return NULL;
+    return nullptr;
 }
 
 void MockedLevelStorage::checkSession()
@@ -18,7 +18,7 @@ void MockedLevelStorage::checkSession()
 
 ChunkStorage *MockedLevelStorage::createChunkStorage(Dimension *dimension)
 {
-    return NULL;
+    return nullptr;
 }
 
 void MockedLevelStorage::saveLevelData(LevelData *levelData, vector<shared_ptr<Player> > *players)
@@ -31,7 +31,7 @@ void MockedLevelStorage::saveLevelData(LevelData *levelData)
 
 PlayerIO *MockedLevelStorage::getPlayerIO()
 {
-    return NULL;
+    return nullptr;
 }
 
 void MockedLevelStorage::closeAll()