The big NULL replacement party part 1.

This is meant to be a safer alternative since
NULL can often be 0. Let's not rely on that.

And yes, I know this is a lot of files. This is
a safer thing to do in big commits vs for loops.

src/CharacterManager.cpp

@@ -127,7 +127,7 @@ public:
 	static int GetCharacter( T* p, lua_State *L )
 	{
 		Character *pCharacter = p->GetCharacterFromID(SArg(1));
-		if( pCharacter != NULL )
+		if( pCharacter != nullptr )
 			pCharacter->PushSelf( L );
 		else
 			lua_pushnil( L );
@@ -137,7 +137,7 @@ public:
 	static int GetRandomCharacter( T* p, lua_State *L )
 	{
 		Character *pCharacter = p->GetRandomCharacter();
-		if( pCharacter != NULL )
+		if( pCharacter != nullptr )
 			pCharacter->PushSelf( L );
 		else
 			lua_pushnil( L );