In the Smart contract day22-ICO/ICO.sol is a critical logic error.

the modifier tokensReleased and tokensNotReleased depend on the boolean released.
This boolean never gets set to true in the release() function.

Therefore the withdraw function can never be called after deployment of the current implementation.

I will open a PR addressing this simple fix.

My proposed change would be the following:

function release() external onlyAdmin icoEnded tokensNotReleased {
  released = true;
  DoneToken tokenInstance = DoneToken(token);
  for (uint256 i = 0; i < sales.length; i  ) {
    Sale storage sale = sales[i];
    tokenInstance.transfer(sale.investor, sale.quantity);
  }
}