I don't think this breaks existing code. The [documentation](http://www.openframeworks.cc/documentation/serial/ofSerial.html#writeByte) says it returns true on success...

actually, would anyone be opposed to a version of writeByte that just called writeBytes with a length of 1 ? in order to avoid duplicating all the platform-dependent code that's inside both writeByte and writeBytes right now...?

I would gladly PR this if there's consensus...