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/IniFile.cpp

@@ -165,7 +165,7 @@ bool IniFile::DeleteKey(const RString &keyname)
 bool IniFile::RenameKey(const RString &from, const RString &to)
 {
 	// If to already exists, do nothing.
-	if( GetChild(to) != NULL )
+	if( GetChild(to) != nullptr )
 		return false;
 
 	XNode* pNode = GetChild( from );