CVarManager: Bring back de/serialization

Runtime/Streams/CTextInStream.hpp

@@ -0,0 +1,14 @@
+#pragma once
+#include "Runtime/Streams/CInputStream.hpp"
+
+namespace metaforce {
+class CTextInStream {
+  CInputStream* m_in;
+  s32 m_len;
+public:
+  CTextInStream(CInputStream& in, int len);
+
+  bool IsEOF() { return m_in->GetReadPosition() >= m_len; }
+  std::string GetNextLine();
+};
+}