Modernize project codebase (#906)

* 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

* Add safety checks and fix a issue with vector going OOR

Minecraft.Client/Common/GameRules/GameRule.h

@@ -40,7 +40,7 @@ public:
 	stringValueMapType m_parameters; // These are the members of this rule that maintain it's state
 
 public:
-	GameRule(GameRuleDefinition *definition, Connection *connection = NULL);
+	GameRule(GameRuleDefinition *definition, Connection *connection = nullptr);
 	virtual ~GameRule();
 
 	Connection *getConnection() { return m_connection; }