[RFC] Basic syslog for trust router

These changes log the result of trust path requests transiting the trust router and certain kinds of failure into syslog.

This will allow any log aggregator that supports syslog as a transport (namely graylog2, but pretty much every log management tool supports syslog).

Making this work in trust_router has the side effect of also making it work in the standalone TIDS, however this is currently hard coded as disabled because the only configuration mechanism TIDS has for configuration is the ever-growing command line.

This has received basic testing, but should not yet be merged.

Comments appreciated.