backlog/169

Implements the issue https://github.com/telefonicaid/fiware-connectors/issues/169 (get version operation)
Are you talking about modifying the content? Or the file name? If the file name is changed the stream will be null and a "UNKNOWN" commit hash will be printed. If the content is changed... well, I think I could at least check it is an hexadecimal 40 bytes lenght string. But that not avoids anyone can change the content with another valid string.