I can't install, I get the message that you are an 'Unidentified Developer' on my MAC.
What you will need to do is:
1. Try to open the program by right clicking on it and selecting 'Open'. If you do not have the option to right click, try holding down Ctrl and clicking.
2. You will then get the warning stating our editor is 'from an unidentified developer. Are you sure you want to open it?' with the options 'Open' or 'Cancel'. Click 'Open'.
3. You will receive a warning that it is not a recognised program but it should also direct you how to open the program.