RSysLog implementation

Hi !
I'm pretty new to NodeJS... I tried to implement the rsyslog transport.

Actually I wrote a simple implementation, but I've added some test (I don't know yet vow, so I copied/adapted the tests I've seen on webhook transport).

Just let me know if You'll grab this pull request or if I should build a brand new project (like winston-sns, winston-graylog2, etc...)

Maybe this could close the issue # 304....

Regards
FabioG