Warning: Header may not contain more than a single header, new line detected

When outputting an error, we show the exception message in the header:

```
	public function output() {
		header($_SERVER["SERVER_PROTOCOL"] . ' ' . $this->getCode() . ' ' . $this->getMessage(), true);

```

in lib/Skeleton/Application/Api/Exception.php

Can you please make sure newlines are removed from the exception and the length of the message is limited to the maximum length of a header line.