Change the mechanism for adding new line character (i.e. '\n\) to log messages in some loggers.

[mskoleck]

Currently both in DDFileLogger and DDTTYLogger the '\n' character is added to each outputted string if the output does not end with the newline. This means that some custom formattings which would like to output multiple log messages in the same line are not possible.

Would it be possible to change both of those loggers not to add the newline character in case when the custom formatter is used. Then developers could provide their own formatters that would allow more control over the messages. Standard formatting would still add the newline character in the default case.

In case of DDFileLogger it just requires moving the line appending code from the log message to the default formatter. In case of DDTTYLogger it requires not adding the 5th element of the iovec struct array.

In case of ASL logger, the format is controlled by the asl api so no change is needed there.

[rivera-ernesto]

Maybe a addNewLineToLogMessagesIfNeeded flag (default YES) would be handy.

Pull request? ;)

[bpoplauschi]

Fixed by #310