Added 'syslog_output' support.

I added 'syslog_output' support.  This can help out in a decentralized or dynamic environment, where you might have to use OSSEC in local mode, but want to ship alerts somewhere, without the complexity of agent mode or an OSSEC server.

FYI: OSSEC ships via UDP, so you might want to use rsyslog or nxlog locally to relay this reliably, via TCP. If you want to secure the transport as well, I'd  suggest NXlog's SSL output module.
Raw ruby is nice :smile: but this is kind of hard to read. How about something like `not_if "grep -i #{ossec_plist} csyslog_daemon"`? Grep can handle both of these cases, and while shelling out is strictly less good, it's more idiomatic in this context.