message: Remove unused functions firstSpender(), doubleSpender()
diff: @@ -40,8 +40,6 @@ public:
  std::vector<std::vector<uint8_t> > pushData;
  };
  - Spender firstSpender() const { return m_spender1; }
  - Spender doubleSpender() const { return m_spender2; }
  // old fashioned serialization.
  ADD_SERIALIZE_METHODS
  