message: [zPIV] publicCoinSpend version field included in the serialization for any future change.
diff: #include "zpiv/zerocoin.h"
  #include "chainparams.h"
  +static int const COIN_SPEND_PUBLIC_SPEND_VERSION = 3;
  +
  class PublicCoinSpend : public libzerocoin::CoinSpend{
  public:
  @@ -30,6 +32,7 @@ public:
  this->randomness = randomness;
  this->pubkey = pubkey;
  this->spendType = libzerocoin::SpendType::SPEND;
  + this->version = COIN_SPEND_PUBLIC_SPEND_VERSION;
  };
  template <typename Stream>
  @@ -40,8 +43,6 @@ public:
  this->spendType = libzerocoin::SpendType::SPEND;
  }
  - uint8_t getVersion() const { return libzerocoin::PrivateCoin::PUBKEY_VERSION; }
  -
  const uint256 signatureHash() const override;
  void setVchSig(std::vector<unsigned char> vchSig) { this->vchSig = vchSig; };
  bool Verify(const libzerocoin::Accumulator& a, bool verifyParams = true) const override;
  @@ -58,6 +59,7 @@ public:
  template <typename Stream, typename Operation>
  inline void SerializationOp(Stream& s, Operation ser_action, int nType, int nVersion) {
  + READWRITE(version);
  READWRITE(coinSerialNumber);
  READWRITE(randomness);
  READWRITE(pubkey);
  