Better CLI factory error exception message

Now when CLI factory finds an error it outputs the error message to avoid needing to check the log and the exception raised.

Also adds a specific exception for CLI factory CLIFactoryError which is
raised when any entity could not be created via CLI.
There is no need to do that python does not need to be a unicode string when raising and exception as is demonstrated on [1]

[1] https://docs.python.org/2/tutorial/errors.html#raising-exceptions