onHoldBalance implementation

  function onHoldBalanceOf(address _storageContract, address _account)
  constant returns (uint256 balance)
  {
    return EternalStorage(_storageContract).getUIntValue(keccak256("onhold:", _account));
  }

  function onHoldBalanceSet(address _storageContract, address _account, uint256 _balance)
  {
    var onHoldBalance = EternalStorage(_storageContract).getUIntValue(keccak256("onhold:", _account));
    EternalStorage(_storageContract).setUIntValue(keccak256("onhold:", _account), onHoldBalance + _balance);
  }

  function releaseTokens(address _storageContract, address _account)
  {
    var onHoldBalance = onHoldBalanceOf(_storageContract, _account);
    if (onHoldBalance > 0) {
      EternalStorage(_storageContract).setUIntValue(keccak256("onhold:", _account), 0);

      var balance = balanceOf(_storageContract, _account);
      EternalStorage(_storageContract).setUIntValue(keccak256("balance:", _account), balance + onHoldBalance);
    }
  }