removes newline from the message

Hi,
I've noticed that an HTML multiline message will be rejected beacuse it will produce a wrang JSON object.

You are appending ```<br/>``` at the end of each lines but not removing the ```\n```

This small fix will removes all the ```\n``` and ```\r``` in the message before sending it.


I've tested it on OS X 10.9 and CentOS 7