Added feature to send log message to remote syslog server over UDP or TCP.

See VyOS bug 195 for more information about the feature request. (http://bugzilla.vyos.net/show_bug.cgi?id=195)

The following configuration should be possible to create:
```
        host host1.example.com {
            facility all {
                level debug
            }
        }
        host host2.example.com {
            facility all {
                level info
                protocol tcp
            }
        }
        host host3.example.com {
            facility all {
                protocol udp
            }
        }
```

After commit the following file should be generated:
/etc/rsyslog.d/vyatta-log.conf
```
*.debug @host1.example.com
*.info @@host2.example.com
*.err @host3.example.com
```